Downlink control signaling

ABSTRACT

Techniques for efficient downlink control with a large number of carriers and/or TTIs are described. Techniques for blind decoding reduction may include making the search space and/or aggregation level of candidates for a first PDCCH/E-PDCCH associated with the characteristics of a second received PDCCH/E-PDCCH. Techniques may include embedding DCI for a set of serving cells and/or TTIs in a PDSCH. DCI for a set of serving cells and/or TTIs may be included in single PDCCH/E-PDCCH. To reduce overhead, carrier indicator field interpretation may be associated with the serving cell or TTI from which the PDCCH/E-PDCCH containing the downlink control information is received, or the group of cells or TTIs to which the PDCCH/E-PDCCH containing the downlink control information belongs.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 62/109,003, filed Jan. 28, 2015, of U.S. ProvisionalPatent Application No. 62/144,861, filed Apr. 8, 2015, and of U.S.Provisional Patent Application No. 62/161,089, filed May 13, 2015, thecontents of which are incorporated by reference herein.

BACKGROUND

Carrier aggregation for LTE was introduced in 3GPP Release 10. Carrieraggregation allows a WTRU to transmit and/or receive on more than onecarrier simultaneously, which can result in an increase of peak datarate over the air interface. According to Release 10 operation, themaximum number of carriers that can be aggregated may be up to five (5),for a potential maximum bandwidth of 100 MHz.

Transmission of data in the downlink and uplink in LTE may be performedusing the physical downlink shared channel (PDSCH) and/or physicaluplink shared channel (PUSCH). The network can dynamically indicatedownlink control information (DCI) pertaining to a certain PDSCH orPUSCH transmission using the physical downlink control channel (PDCCH)and/or the enhanced physical downlink control channel (E-PDCCH), forexample on a per-subframe basis. To receive the PDCCH and/or E-PDCCH, awireless transmit/receive unit (WTRU) may perform blink decoding, duringwhich the WTRU may attempt reception of the DCI in one or more searchspaces. One or more, or each, search space may include a number of PDCCHor E-PDCCH candidates which the WTRU attempts to decode.

SUMMARY

Carrier aggregation may be used to increase overall system throughput,increase individual WTRU data rates, and/or allow the network to serve alarger number of WTRUs relatively simultaneously. Techniques forreducing blind decoding and overhead may improve the efficiency forcarrier aggregation implementation. For example, the search space and/oraggregation level of carriers or TTIs may be associated with thecharacteristics of a second received PDCCH/E-PDCCH. To reduce overhead,carrier indicator field interpretation may be associated with theserving cell or TTI from which the PDCCH/E-PDCCH containing the downlinkcontrol information is received, or the group of cells or TTIs to whichthe PDCCH/E-PDCCH containing the downlink control information belongs.

A wireless transmit/receive unit (WTRU) may implement a method forefficient downlink control or be configured to perform the method. Forexample, the WTRU may decode first downlink control information (DCI)via a downlink control channel of a first serving cell. The first DCImay include scheduling information for a first physical downlink sharedchannel (PDSCH) transmission received by the WTRU via the first servingcell. The WTRU may receive the first PDSCH transmission via the firstserving cell in accordance with the first DCI. The first PDSCHtransmission may comprise a second DCI. The second DCI may comprisescheduling information for a second physical downlink shared channeltransmission (PDSCH) transmission received by the WTRU via a secondserving cell. The WTRU may receive the second PDSCH transmission via thesecond serving cell in accordance with the second DCI.

For example, bits of the second DCI may be multiplexed with bits of atransport channel used for user data transmission in the first PDSCHtransmission. The bits of the second DCI and the bits of the transportchannel used for user data transmission may be multiplexed fortransmission prior to being mapped to modulated symbols of the firstPDSCH transmission. The WTRU may determine a first cyclic redundancycheck (CRC) for the bits of the second DCI and a second CRC for the bitsof the transport channel used for user data transmission. In the method,the bits of the second DCI may be mapped to specific modulated symbolsof the first PDSCH transmission. The WTRU may determine to whichmodulated symbols of the first PDSCH transmission the second DCI ismapped to based on one or more of a cell identification (ID) of thesecond cell, a WTRU ID used by the WTRU in the second cell, a subframenumber of the second cell, or a component carrier number of the secondcell. The first DCI may include an indication of whether or not thesecond DCI is to be included in the first PDSCH transmission. Theindication of whether or not the second DCI is to be included in thefirst PDSCH transmission may correspond to a flag bit in the first DCI.The indication of whether or not the second DCI is to be included in thefirst PDSCH transmission may correspond to a code point setting in thefirst DCI. The indication of whether or not the second DCI is to beincluded in the first PDSCH transmission may correspond to a sequence ofphase values of known time symbols. The indication of whether or not thesecond DCI is to be included in the first PDSCH transmission maycorresponds to a sequence of phase values of known frequency symbols.

In the method, the downlink control channel may correspond to one of aphysical downlink control channel (PDCCH) or an enhanced PDCCH(E-PDCCH). The WTRU may send feedback indicating whether the second DCIis successfully decoded from the first PDSCH transmission. The feedbackmay be separate from an acknowledgement of user data reception from thefirst PDSCH transmission. The WTRU may send the feedback at regular timeintervals. The WTRU may send the feedback when inquired by an eNB abouta success rate of decoding DCIs.

For example, the WTRU may decode first downlink control information(DCI) via a downlink control channel of a first serving cell. The firstDCI may include scheduling information for a first physical downlinkshared channel (PDSCH) transmission received by the WTRU via a firstserving cell. The WTRU may decode a second DCI via the downlink controlchannel of the first serving cell. The WTRU may receive the first PDSCHtransmission via the first serving cell in accordance with the firstDCI. The first DCI may be associated with a second DCI. The second DCImay include scheduling information for a second physical downlink sharedchannel (PDSCH) transmission received by the WTRU via a second servingcell. The WTRU may receive the second PDSCH transmission via the secondserving cell in accordance with the second DCI. The downlink controlchannel may correspond to one of a physical downlink control channel(PDCCH) or an enhanced PDCCH (E-PDCCH). The first and second PDSCHtransmissions may include a plurality of transport blocks (TBs). Eachtransport block may be associated with one of the first or secondserving cell. The DCI may include a single set of scheduling parameters.The WTRU may use the single set of scheduling parameters for theplurality of TBs. The DCI may include multiple sets of schedulingparameters. One set of the plurality of scheduling parameters may beassociated with each cell. The TB may include a plurality of physicalresource blocks (PRBs). Each of the PRBs may be associated with one ofthe plurality of cells.

A wireless transmit/receive unit (WTRU) may implement a method or beconfigured to perform the method for determining the validity of a DCI.For example, the WTRU may receive first downlink control channeltransmission (DCI). The WTRU may determine a plurality of cyclicredundancy check (CRC) parity bits for a first candidate downlinkcontrol information (DCI) from the first downlink control channeltransmission. The WTRU may attempt descrambling the plurality of CRCparity bits for the first candidate DCI using a radio network temporaryidentifier (RNTI) of the WTRU and a valid potential value for at leastone field included in the first candidate DCI. The WTRU may determinethat the first candidate DCI is valid and applicable to the WTRU basedon successfully descrambling the plurality of CRC parity bits for thefirst candidate DCI using the RNTI of the WTRU and the valid potentialvalue for the at least one field included in the first candidate DC. Theat least one field included in the first candidate DCI may contain adownlink antenna indicator (DAI) field. The WTRU may use concatenatedbits of the RNTI of the WTRU and of the valid potential value for the atleast one field in order to successfully descramble the plurality of CRCparity bits. The WTRU determining that the first candidate DCI is validand applicable to the WTRU may be further based on successfullydescrambling a second DCI. The second DCI and the first candidate DCImay be both received via the downlink control channel of a first cell.The second DCI and the first candidate DCI may be received via thedownlink control channel of different cells. The WTRU may determine atype of DCI included in the first candidate DCI based on one or more ofa received configuration, the RNTI used to decode the downlink controlchannel transmission, a location of the downlink control channeltransmission in a search space, the search space utilized, or a CRCpolynomial utilized. The WTRU may determine which cell the firstcandidate DCI is applicable to based on a value of a field in the firstcandidate DCI. The serving cell may correspond to a certain field.

A wireless transmit/receive unit (WTRU) may implement a method or beconfigured to perform the method for TTI aggregation. For example, theWTRU may decode first downlink control information (DCI) via a downlinkcontrol channel in a first transmission time interval (TTI). The firstDCI may comprise scheduling information for a first physical downlinkshared channel (PDSCH) transmission for the WTRU sent in the first TTI.The WTRU may determine a decoding assumption to use when attempting todecode a second DCI via the downlink control channel based on a propertyof the first DCI. The second DCI may include scheduling information fora second PDSCH transmission for the WTRU sent in a second TTI. The WTRUmay receive the second DCI. The WTRU may receive the first PDSCHtransmission in the first TTI in accordance with the first DCI. The WTRUmay receive the second PDSCH transmission in the second TTI inaccordance with the first DCI. The second DCI may be received in thefirst TTI. The second DCI may be received in the second TTI. Theproperty of the first DCI may correspond to an aggregation level usedfor decoding the first DCI. The decoding assumption may includeattempting to decode the second DCI using the same aggregation level aswas used for decoding the first DCI.

A wireless transmit/receive unit (WTRU) may implement a method or beconfigured to perform the method for overhead reduction. For example,the WTRU may receive downlink control information (DCI) via a downlinkcontrol channel of in a first transmission time interval (TTI). The DCImay include scheduling information for one or more physical downlinkshared channel (PDSCH) transmissions received by the WTRU via aplurality TTIs. The WTRU may determine which TTIs correspond to theplurality of TTIs according to a group identity contained in the DCI.The WTRU may receive the one or more PDSCH transmissions during theplurality of TTIs in accordance with the DCI. The group identity may bedetermined based on at least a carrier indicator field (CIF) of the DCIand the identity of the first TTI during which the first DCI wasreceived. For example, the WTRU may determine which cell a given CIFvalue is referring to based on the identity of the serving cell overwhich the CIF (e.g., DCI) was received.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description of example embodiments is providedwith reference to the appended drawings. For the purposes ofillustration, the drawings show example embodiments. The contemplatedsubject matter is not limited to the specific elements and/orinstrumentalities described or illustrated. And absent specific notationto the contrary, no subject matter is contemplated as necessary and/oressential. In addition, the described embodiments may be employed in anycombination, in whole or in part. In the drawings:

FIG. 1A is a system diagram of an example communications system in whichone or more disclosed embodiments may be implemented.

FIG. 1B is a system diagram of an example wireless transmit/receive unit(WTRU) that may be used within the communications system illustrated inFIG. 1A.

FIG. 1C is a system diagram of an example radio access network and anexample core network that may be used within the communications systemillustrated in FIG. 1A.

FIG. 1D is a system diagram of another example radio access network andan example core network that may be used within the communicationssystem illustrated in FIG. 1A.

FIG. 1E is a system diagram of another example radio access network andan example core network that may be used within the communicationssystem illustrated in FIG. 1A.

DETAILED DESCRIPTION

A detailed description of example embodiments will now be described withreference to the various Figures. Although this description provides adetailed example of possible implementations, it should be noted thatthe details are intended to be examples and in no way limit the scope ofthe application. As used herein, the article “a” or “an”, absent furtherqualification or characterization, may be understood to mean “one ormore” or “at least one”, for example. Also, as used herein, the phraseuser equipment (UE) may be understood to mean the same thing as thephrase wireless transmit/receive unit (WTRU).

FIG. 1A is a diagram of an example communications system 100 in whichone or more disclosed embodiments may be implemented. The communicationssystem 100 may be a multiple access system that provides content, suchas voice, data, video, messaging, broadcast, etc., to multiple wirelessusers. The communications system 100 may enable multiple wireless usersto access such content through the sharing of system resources,including wireless bandwidth. For example, the communications systems100 may employ one or more channel access methods, such as code divisionmultiple access (CDMA), time division multiple access (TDMA), frequencydivision multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrierFDMA (SC-FDMA), and the like.

As shown in FIG. 1A, the communications system 100 may include wirelesstransmit/receive units (WTRUs) 102 a, 102 b, 102 c, and/or 102 d (whichgenerally or collectively may be referred to as WTRU 102), a radioaccess network (RAN) 103/104/105, a core network 106/107/109, a publicswitched telephone network (PSTN) 108, the Internet 110, and othernetworks 112, though it will be appreciated that the disclosedembodiments contemplate any number of WTRUs, base stations, networks,and/or network elements. Each of the WTRUs 102 a, 102 b, 102 c, 102 dmay be any type of device configured to operate and/or communicate in awireless environment. By way of example, the WTRUs 102 a, 102 b, 102 c,102 d may be configured to transmit and/or receive wireless signals andmay include user equipment (UE), a mobile station, a fixed or mobilesubscriber unit, a pager, a cellular telephone, a personal digitalassistant (PDA), a smartphone, a laptop, a netbook, a personal computer,a wireless sensor, consumer electronics, and the like.

The communications systems 100 may also include a base station 114 a anda base station 114 b. Each of the base stations 114 a, 114 b may be anytype of device configured to wirelessly interface with at least one ofthe WTRUs 102 a, 102 b, 102 c, 102 d to facilitate access to one or morecommunication networks, such as the core network 106/107/109, theInternet 110, and/or the networks 112. By way of example, the basestations 114 a, 114 b may be a base transceiver station (BTS), a Node-B,an eNode B, a Home Node B, a Home eNode B, a site controller, an accesspoint (AP), a wireless router, and the like. While the base stations 114a, 114 b are each depicted as a single element, it will be appreciatedthat the base stations 114 a, 114 b may include any number ofinterconnected base stations and/or network elements.

The base station 114 a may be part of the RAN 103/104/105, which mayalso include other base stations and/or network elements (not shown),such as a base station controller (BSC), a radio network controller(RNC), relay nodes, etc. The base station 114 a and/or the base station114 b may be configured to transmit and/or receive wireless signalswithin a particular geographic region, which may be referred to as acell (not shown). The cell may further be divided into cell sectors. Forexample, the cell associated with the base station 114 a may be dividedinto three sectors. Thus, in one embodiment, the base station 114 a mayinclude three transceivers, i.e., one for each sector of the cell. Inanother embodiment, the base station 114 a may employ multiple-inputmultiple output (MIMO) technology and, therefore, may utilize multipletransceivers for each sector of the cell.

The base stations 114 a, 114 b may communicate with one or more of theWTRUs 102 a, 102 b, 102 c, 102 d over an air interface 115/116/117,which may be any suitable wireless communication link (e.g., radiofrequency (RF), microwave, infrared (IR), ultraviolet (UV), visiblelight, etc.). The air interface 115/116/117 may be established using anysuitable radio access technology (RAT).

More specifically, as noted above, the communications system 100 may bea multiple access system and may employ one or more channel accessschemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. Forexample, the base station 114 a in the RAN 103/104/105 and the WTRUs 102a, 102 b, 102 c may implement a radio technology such as UniversalMobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA),which may establish the air interface 115/116/117 using wideband CDMA(WCDMA). WCDMA may include communication protocols such as High-SpeedPacket Access (HSPA) and/or Evolved HSPA (HSPA+). HSPA may includeHigh-Speed Downlink Packet Access (HSDPA) and/or High-Speed UplinkPacket Access (HSUPA).

In another embodiment, the base station 114 a and the WTRUs 102 a, 102b, 102 c may implement a radio technology such as Evolved UMTSTerrestrial Radio Access (E-UTRA), which may establish the air interface115/116/117 using Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A).

In other embodiments, the base station 114 a and the WTRUs 102 a, 102 b,102 c may implement radio technologies such as IEEE 802.16 (i.e.,Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000,CDMA2000 1×, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), InterimStandard 95 (IS-95), Interim Standard 856 (IS-856), Global System forMobile communications (GSM), Enhanced Data rates for GSM Evolution(EDGE), GSM EDGE (GERAN), and the like.

The base station 114 b in FIG. 1A may be a wireless router, Home Node B,Home eNode B, or access point, for example, and may utilize any suitableRAT for facilitating wireless connectivity in a localized area, such asa place of business, a home, a vehicle, a campus, and the like. In oneembodiment, the base station 114 b and the WTRUs 102 c, 102 d mayimplement a radio technology such as IEEE 802.11 to establish a wirelesslocal area network (WLAN). In another embodiment, the base station 114 band the WTRUs 102 c, 102 d may implement a radio technology such as IEEE802.15 to establish a wireless personal area network (WPAN). In yetanother embodiment, the base station 114 b and the WTRUs 102 c, 102 dmay utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE,LTE-A, etc.) to establish a picocell or femtocell. As shown in FIG. 1A,the base station 114 b may have a direct connection to the Internet 110.Thus, the base station 114 b may not be required to access the Internet110 via the core network 106/107/109.

The RAN 103/104/105 may be in communication with the core network106/107/109, which may be any type of network configured to providevoice, data, applications, and/or voice over internet protocol (VoIP)services to one or more of the WTRUs 102 a, 102 b, 102 c, 102 d. Forexample, the core network 106/107/109 may provide call control, billingservices, mobile location-based services, pre-paid calling, Internetconnectivity, video distribution, etc., and/or perform high-levelsecurity functions, such as user authentication. Although not shown inFIG. 1A, it will be appreciated that the RAN 103/104/105 and/or the corenetwork 106/107/109 may be in direct or indirect communication withother RANs that employ the same RAT as the RAN 103/104/105 or adifferent RAT. For example, in addition to being connected to the RAN103/104/105, which may be utilizing an E-UTRA radio technology, the corenetwork 106/107/109 may also be in communication with another RAN (notshown) employing a GSM radio technology.

The core network 106/107/109 may also serve as a gateway for the WTRUs102 a, 102 b, 102 c, 102 d to access the PSTN 108, the Internet 110,and/or other networks 112. The PSTN 108 may include circuit-switchedtelephone networks that provide plain old telephone service (POTS). TheInternet 110 may include a global system of interconnected computernetworks and devices that use common communication protocols, such asthe transmission control protocol (TCP), user datagram protocol (UDP)and the internet protocol (TP) in the TCP/IP internet protocol suite.The networks 112 may include wired or wireless communications networksowned and/or operated by other service providers. For example, thenetworks 112 may include another core network connected to one or moreRANs, which may employ the same RAT as the RAN 103/104/105 or adifferent RAT.

Some or all of the WTRUs 102 a, 102 b, 102 c, 102 d in thecommunications system 100 may include multi-mode capabilities, i.e., theWTRUs 102 a, 102 b, 102 c, 102 d may include multiple transceivers forcommunicating with different wireless networks over different wirelesslinks. For example, the WTRU 102 c shown in FIG. 1A may be configured tocommunicate with the base station 114 a, which may employ acellular-based radio technology, and with the base station 114 b, whichmay employ an IEEE 802 radio technology.

FIG. 1B is a system diagram of an example WTRU 102. As shown in FIG. 1B,the WTRU 102 may include a processor 118, a transceiver 120, atransmit/receive element 122, a speaker/microphone 124, a keypad 126, adisplay/touchpad 128, non-removable memory 130, removable memory 132, apower source 134, a global positioning system (GPS) chipset 136, andother peripherals 138. It will be appreciated that the WTRU 102 mayinclude any sub-combination of the foregoing elements while remainingconsistent with an embodiment. Also, embodiments contemplate that thebase stations 114 a and 114 b, and/or the nodes that base stations 114 aand 114 b may represent, such as but not limited to transceiver station(BTS), a Node-B, a site controller, an access point (AP), a home node-B,an evolved home node-B (eNodeB), a home evolved node-B (HeNB), a homeevolved node-B gateway, and proxy nodes, among others, may include someor all of the elements depicted in FIG. 1B and described herein.

The processor 118 may be a general purpose processor, a special purposeprocessor, a conventional processor, a digital signal processor (DSP), aplurality of microprocessors, one or more microprocessors in associationwith a DSP core, a controller, a microcontroller, Application SpecificIntegrated Circuits (ASICs), Field Programmable Gate Array (FPGAs)circuits, any other type of integrated circuit (IC), a state machine,and the like. The processor 118 may perform signal coding, dataprocessing, power control, input/output processing, and/or any otherfunctionality that enables the WTRU 102 to operate in a wirelessenvironment. The processor 118 may be coupled to the transceiver 120,which may be coupled to the transmit/receive element 122. While FIG. 1Bdepicts the processor 118 and the transceiver 120 as separatecomponents, it will be appreciated that the processor 118 and thetransceiver 120 may be integrated together in an electronic package orchip.

The transmit/receive element 122 may be configured to transmit signalsto, or receive signals from, a base station (e.g., the base station 114a) over the air interface 115/116/117. For example, in one embodiment,the transmit/receive element 122 may be an antenna configured totransmit and/or receive RF signals. In another embodiment, thetransmit/receive element 122 may be an emitter/detector configured totransmit and/or receive IR, UV, or visible light signals, for example.In yet another embodiment, the transmit/receive element 122 may beconfigured to transmit and receive both RF and light signals. It will beappreciated that the transmit/receive element 122 may be configured totransmit and/or receive any combination of wireless signals.

In addition, although the transmit/receive element 122 is depicted inFIG. 1B as a single element, the WTRU 102 may include any number oftransmit/receive elements 122. More specifically, the WTRU 102 mayemploy MIMO technology. Thus, in one embodiment, the WTRU 102 mayinclude two or more transmit/receive elements 122 (e.g., multipleantennas) for transmitting and receiving wireless signals over the airinterface 115/116/117.

The transceiver 120 may be configured to modulate the signals that areto be transmitted by the transmit/receive element 122 and to demodulatethe signals that are received by the transmit/receive element 122. Asnoted above, the WTRU 102 may have multi-mode capabilities. Thus, thetransceiver 120 may include multiple transceivers for enabling the WTRU102 to communicate via multiple RATs, such as UTRA and IEEE 802.11, forexample.

The processor 118 of the WTRU 102 may be coupled to, and may receiveuser input data from, the speaker/microphone 124, the keypad 126, and/orthe display/touchpad 128 (e.g., a liquid crystal display (LCD) displayunit or organic light-emitting diode (OLED) display unit). The processor118 may also output user data to the speaker/microphone 124, the keypad126, and/or the display/touchpad 128. In addition, the processor 118 mayaccess information from, and store data in, any type of suitable memory,such as the non-removable memory 130 and/or the removable memory 132.The non-removable memory 130 may include random-access memory (RAM),read-only memory (ROM), a hard disk, or any other type of memory storagedevice. The removable memory 132 may include a subscriber identitymodule (SIM) card, a memory stick, a secure digital (SD) memory card,and the like. In other embodiments, the processor 118 may accessinformation from, and store data in, memory that is not physicallylocated on the WTRU 102, such as on a server or a home computer (notshown).

The processor 118 may receive power from the power source 134, and maybe configured to distribute and/or control the power to the othercomponents in the WTRU 102. The power source 134 may be any suitabledevice for powering the WTRU 102. For example, the power source 134 mayinclude one or more dry cell batteries (e.g., nickel-cadmium (NiCd),nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion),etc.), solar cells, fuel cells, and the like.

The processor 118 may also be coupled to the GPS chipset 136, which maybe configured to provide location information (e.g., longitude andlatitude) regarding the current location of the WTRU 102. In additionto, or in lieu of, the information from the GPS chipset 136, the WTRU102 may receive location information over the air interface 115/116/117from a base station (e.g., base stations 114 a, 114 b) and/or determineits location based on the timing of the signals being received from twoor more nearby base stations. It will be appreciated that the WTRU 102may acquire location information by way of any suitablelocation-determination method while remaining consistent with anembodiment.

The processor 118 may further be coupled to other peripherals 138, whichmay include one or more software and/or hardware modules that provideadditional features, functionality and/or wired or wirelessconnectivity. For example, the peripherals 138 may include anaccelerometer, an e-compass, a satellite transceiver, a digital camera(for photographs or video), a universal serial bus (USB) port, avibration device, a television transceiver, a hands free headset, aBluetooth® module, a frequency modulated (FM) radio unit, a digitalmusic player, a media player, a video game player module, an Internetbrowser, and the like.

FIG. 1C is a system diagram of the RAN 103 and the core network 106according to an embodiment. As noted above, the RAN 103 may employ aUTRA radio technology to communicate with the WTRUs 102 a, 102 b, 102 cover the air interface 115. The RAN 103 may also be in communicationwith the core network 106. As shown in FIG. 1C, the RAN 103 may includeNode-Bs 140 a, 140 b, 140 c, which may each include one or moretransceivers for communicating with the WTRUs 102 a, 102 b, 102 c overthe air interface 115. The Node-Bs 140 a, 140 b, 140 c may each beassociated with a particular cell (not shown) within the RAN 103. TheRAN 103 may also include RNCs 142 a, 142 b. It will be appreciated thatthe RAN 103 may include any number of Node-Bs and RNCs while remainingconsistent with an embodiment.

As shown in FIG. 1C, the Node-Bs 140 a, 140 b may be in communicationwith the RNC 142 a. Additionally, the Node-B 140 c may be incommunication with the RNC 142 b. The Node-Bs 140 a, 140 b, 140 c maycommunicate with the respective RNCs 142 a, 142 b via an Iub interface.The RNCs 142 a, 142 b may be in communication with one another via anIur interface. Each of the RNCs 142 a, 142 b may be configured tocontrol the respective Node-Bs 140 a, 140 b, 140 c to which it isconnected. In addition, each of the RNCs 142 a, 142 b may be configuredto carry out or support other functionality, such as outer loop powercontrol, load control, admission control, packet scheduling, handovercontrol, macro diversity, security functions, data encryption, and thelike.

The core network 106 shown in FIG. 1C may include a media gateway (MGW)144, a mobile switching center (MSC) 146, a serving GPRS support node(SGSN) 148, and/or a gateway GPRS support node (GGSN) 150. While each ofthe foregoing elements are depicted as part of the core network 106, itwill be appreciated that any one of these elements may be owned and/oroperated by an entity other than the core network operator.

The RNC 142 a in the RAN 103 may be connected to the MSC 146 in the corenetwork 106 via an IuCS interface. The MSC 146 may be connected to theMGW 144. The MSC 146 and the MGW 144 may provide the WTRUs 102 a, 102 b,102 c with access to circuit-switched networks, such as the PSTN 108, tofacilitate communications between the WTRUs 102 a, 102 b, 102 c andtraditional land-line communications devices.

The RNC 142 a in the RAN 103 may also be connected to the SGSN 148 inthe core network 106 via an IuPS interface. The SGSN 148 may beconnected to the GGSN 150. The SGSN 148 and the GGSN 150 may provide theWTRUs 102 a, 102 b, 102 c with access to packet-switched networks, suchas the Internet 110, to facilitate communications between and the WTRUs102 a, 102 b, 102 c and IP-enabled devices.

As noted above, the core network 106 may also be connected to thenetworks 112, which may include other wired or wireless networks thatare owned and/or operated by other service providers.

FIG. 1D is a system diagram of the RAN 104 and the core network 107according to an embodiment. As noted above, the RAN 104 may employ anE-UTRA radio technology to communicate with the WTRUs 102 a, 102 b, 102c over the air interface 116. The RAN 104 may also be in communicationwith the core network 107.

The RAN 104 may include eNode-Bs 160 a, 160 b, 160 c, though it will beappreciated that the RAN 104 may include any number of eNode-Bs whileremaining consistent with an embodiment. The eNode-Bs 160 a, 160 b, 160c may each include one or more transceivers for communicating with theWTRUs 102 a, 102 b, 102 c over the air interface 116. In one embodiment,the eNode-Bs 160 a, 160 b, 160 c may implement MIMO technology. Thus,the eNode-B 160 a, for example, may use multiple antennas to transmitwireless signals to, and receive wireless signals from, the WTRU 102 a.

Each of the eNode-Bs 160 a, 160 b, 160 c may be associated with aparticular cell (not shown) and may be configured to handle radioresource management decisions, handover decisions, scheduling of usersin the uplink and/or downlink, and the like. As shown in FIG. 1D, theeNode-Bs 160 a, 160 b, 160 c may communicate with one another over an X2interface.

The core network 107 shown in FIG. 1D may include a mobility managementgateway (MME) 162, a serving gateway 164, and a packet data network(PDN) gateway 166. While each of the foregoing elements are depicted aspart of the core network 107, it will be appreciated that any one ofthese elements may be owned and/or operated by an entity other than thecore network operator.

The MME 162 may be connected to each of the eNode-Bs 160 a, 160 b, 160 cin the RAN 104 via an S1 interface and may serve as a control node. Forexample, the MME 162 may be responsible for authenticating users of theWTRUs 102 a, 102 b, 102 c, bearer activation/deactivation, selecting aparticular serving gateway during an initial attach of the WTRUs 102 a,102 b, 102 c, and the like. The MME 162 may also provide a control planefunction for switching between the RAN 104 and other RANs (not shown)that employ other radio technologies, such as GSM or WCDMA.

The serving gateway 164 may be connected to each of the eNode-Bs 160 a,160 b, 160 c in the RAN 104 via the S1 interface. The serving gateway164 may generally route and forward user data packets to/from the WTRUs102 a, 102 b, 102 c. The serving gateway 164 may also perform otherfunctions, such as anchoring user planes during inter-eNode B handovers,triggering paging when downlink data is available for the WTRUs 102 a,102 b, 102 c, managing and storing contexts of the WTRUs 102 a, 102 b,102 c, and the like.

The serving gateway 164 may also be connected to the PDN gateway 166,which may provide the WTRUs 102 a, 102 b, 102 c with access topacket-switched networks, such as the Internet 110, to facilitatecommunications between the WTRUs 102 a, 102 b, 102 c and IP-enableddevices.

The core network 107 may facilitate communications with other networks.For example, the core network 107 may provide the WTRUs 102 a, 102 b,102 c with access to circuit-switched networks, such as the PSTN 108, tofacilitate communications between the WTRUs 102 a, 102 b, 102 c andtraditional land-line communications devices. For example, the corenetwork 107 may include, or may communicate with, an IP gateway (e.g.,an IP multimedia subsystem (IMS) server) that serves as an interfacebetween the core network 107 and the PSTN 108. In addition, the corenetwork 107 may provide the WTRUs 102 a, 102 b, 102 c with access to thenetworks 112, which may include other wired or wireless networks thatare owned and/or operated by other service providers.

FIG. 1E is a system diagram of the RAN 105 and the core network 109according to an embodiment. The RAN 105 may be an access service network(ASN) that employs IEEE 802.16 radio technology to communicate with theWTRUs 102 a, 102 b, 102 c over the air interface 117. As will be furtherdiscussed below, the communication links between the differentfunctional entities of the WTRUs 102 a, 102 b, 102 c, the RAN 105, andthe core network 109 may be defined as reference points.

As shown in FIG. 1E, the RAN 105 may include base stations 180 a, 180 b,180 c, and an ASN gateway 182, though it will be appreciated that theRAN 105 may include any number of base stations and ASN gateways whileremaining consistent with an embodiment. The base stations 180 a, 180 b,180 c may each be associated with a particular cell (not shown) in theRAN 105 and may each include one or more transceivers for communicatingwith the WTRUs 102 a, 102 b, 102 c over the air interface 117. In oneembodiment, the base stations 180 a, 180 b, 180 c may implement MIMOtechnology. Thus, the base station 180 a, for example, may use multipleantennas to transmit wireless signals to, and receive wireless signalsfrom, the WTRU 102 a. The base stations 180 a, 180 b, 180 c may alsoprovide mobility management functions, such as handoff triggering,tunnel establishment, radio resource management, traffic classification,quality of service (QoS) policy enforcement, and the like. The ASNgateway 182 may serve as a traffic aggregation point and may beresponsible for paging, caching of subscriber profiles, routing to thecore network 109, and the like.

The air interface 117 between the WTRUs 102 a, 102 b, 102 c and the RAN105 may be defined as an R1 reference point that implements the IEEE802.16 specification. In addition, each of the WTRUs 102 a, 102 b, 102 cmay establish a logical interface (not shown) with the core network 109.The logical interface between the WTRUs 102 a, 102 b, 102 c and the corenetwork 109 may be defined as an R2 reference point, which may be usedfor authentication, authorization, IP host configuration management,and/or mobility management.

The communication link between each of the base stations 180 a, 180 b,180 c may be defined as an R8 reference point that includes protocolsfor facilitating WTRU handovers and the transfer of data between basestations. The communication link between the base stations 180 a, 180 b,180 c and the ASN gateway 182 may be defined as an R6 reference point.The R6 reference point may include protocols for facilitating mobilitymanagement based on mobility events associated with each of the WTRUs102 a, 102 b, 102 c.

As shown in FIG. 1E, the RAN 105 may be connected to the core network109. The communication link between the RAN 105 and the core network 109may defined as an R3 reference point that includes protocols forfacilitating data transfer and mobility management capabilities, forexample. The core network 109 may include a mobile IP home agent(MIP-HA) 184, an authentication, authorization, accounting (AAA) server186, and a gateway 188. While each of the foregoing elements aredepicted as part of the core network 109, it will be appreciated thatany one of these elements may be owned and/or operated by an entityother than the core network operator.

The MIP-HA may be responsible for IP address management, and may enablethe WTRUs 102 a, 102 b, 102 c to roam between different ASNs and/ordifferent core networks. The MIP-HA 184 may provide the WTRUs 102 a, 102b, 102 c with access to packet-switched networks, such as the Internet110, to facilitate communications between the WTRUs 102 a, 102 b, 102 cand 1P-enabled devices. The AAA server 186 may be responsible for userauthentication and for supporting user services. The gateway 188 mayfacilitate interworking with other networks. For example, the gateway188 may provide the WTRUs 102 a, 102 b, 102 c with access tocircuit-switched networks, such as the PSTN 108, to facilitatecommunications between the WTRUs 102 a, 102 b, 102 c and traditionalland-line communications devices. In addition, the gateway 188 mayprovide the WTRUs 102 a, 102 b, 102 c with access to the networks 112,which may include other wired or wireless networks that are owned and/oroperated by other service providers.

Although not shown in FIG. 1E, it will be appreciated that the RAN 105may be connected to other ASNs and the core network 109 may be connectedto other core networks. The communication link between the RAN 105 theother ASNs may be defined as an R4 reference point, which may includeprotocols for coordinating the mobility of the WTRUs 102 a, 102 b, 102 cbetween the RAN 105 and the other ASNs. The communication link betweenthe core network 109 and the other core networks may be defined as an R5reference, which may include protocols for facilitating interworkingbetween home core networks and visited core networks.

In view of FIGS. 1A-1E, Base Station 114 a-b, Node B 140 a-c, RNC 142a-b, MSC 146, SGSN 148, MGW 144, CGSN 150, eNode-B 160 a-c, MME 162,Serving Gateway 164, PDN Gateway 166, Base Station 180 a-c, ASN Gateway182, AAA 186, MIP-HA 184, and/or Gateway 188, or the like, may includeone or more of the components described with respect to FIG. 1B, and/ormay function in the same and/or similar manner with respect to thosecomponents as described herein with respect to WTRU 102(a-d), forexample.

In view of FIGS. 1A-1E, and the corresponding description of FIGS.1A-1E, one or more, or all, of the functions described herein withregard to one or more of: WTRU 102 a-d, Base Station 114 a-b, Node B 140a-c, RNC 142 a-b, MSC 146, SGSN 148, MGW 144, CGSN 150, eNode-B 160 a-c,MME 162, Serving Gateway 164, PDN Gateway 166, Base Station 180 a-c, ASNGateway 182, AAA 186, MIP-HA 184, and/or Gateway 188, or the like, maybe performed by one or more emulation devices (not shown) (e.g., one ormore devices configured to emulate one or more, or all, of the functionsdescribed herein).

The one or more emulation devices may be configured to perform the oneor more, or all, functions in one or more modalities. For example, theone or more emulation devices may perform the one or more, or all,functions while being fully or partially implemented/deployed as part ofa wired and/or wireless communication network. The one or more emulationdevices may perform the one or more, or all, functions while beingtemporarily implemented/deployed as part of a wired and/or wirelesscommunication network. The one or more emulation devices may perform theone or more, or all, functions while not being implemented/deployed aspart of a wired and/or wireless communication network (e.g., such as ina testing scenario in a testing laboratory and/or a non-deployed (e.g.testing) wired and/or wireless communication network, and/or testingperformed on one or more deployed components of a wired and/or wirelesscommunication network). The one or more emulation devices may be testequipment.

Carrier aggregation was introduced in Release 10 LTE in order to improvesystem performance. When performing carrier aggregation, rather thanconnecting to a single LTE cell (e.g., where the LTE cell has a cellbandwidth between 1.4 MHz and 20 MHz), WTRUs configured to performcarrier aggregation according to Release 10 LTE may support up to fiveserving cells at once (e.g., the terms serving cell and componentcarrier may be used interchangeably herein), allowing for a maximumaggregated bandwidth of up to 100 MHz. Carrier aggregation is onemechanism available that may be used to increase overall systemthroughput, increase individual WTRU data rates, and/or allow thenetwork to serve a larger number of WTRUs relatively simultaneously. Oneof the serving cells may be a primary serving cell (PCell), and theother (e.g., up to four in R10) serving cells may be secondary servingcells (SCells).

The WTRU may receive downlink data using the physical downlink sharedchannel (PDSCH) and may transmit uplink data on a physical uplink sharedchannel (PUSCH). A PDSCH may be included on each downlink carrier and aPUSCH may be included on each uplink carrier. The network maydynamically indicate downlink control information (DCI) that includesscheduling information for the PDSCH and/or PUSCH using the physicaldownlink control channel (PDCCH) and/or the enhanced physical downlinkcontrol channel (E-PDCCH). Dynamic scheduling of the PDSCH and/or PUSCHmay be performed for each subframe. To receive the PDCCH and/or E-PDCCH,a WTRU may perform blank decoding, during which the WTRU may attemptdecode PDCCH and/or E-PDCCH transmission(s) in one or more search spaceswith the PDCCH and/or E-PDCCH regions. One or more, or each, searchspace may include a number of PDCCH or E-PDCCH candidates which the WTRUattempts to decode to determine if the candidate has DCI applicable tothe WTRU.

There may be a plurality of (e.g., up to six (6)) PDCCH candidates inthe common search space (CSS) in a primary cell. There may be aplurality of (e.g., up to sixteen (16)) candidates of PDCCH and/orE-PDCCH in a WTRU-specific search space (UESS) in one or more activatedserving cell. For example, there may be a plurality of (e.g., up tosixteen (16)) candidates of PDCCH and/or E-PDCCH in a WTRU-specificsearch space (UESS) in each activated serving cell. For one or morecandidate in the UESS or CSS, the WTRU may attempt reception. Forexample, for each candidate in the UESS or CSS, the WTRU may attemptreception. The WTRU may assume that the PDCCH and/or E-PDCCH wastransmitted using one or more payload sizes. For example, the WTRU mayassume that the PDCCH and/or E-PDCCH was transmitted using one of two ormore possible payload sizes. The two or more possible payload sizes maybe determined by a set of DCI formats that the WTRU may be configured toreceive. One or more, or each, such decoding attempt may be referred toas a “blind decoding attempt.” According to Release 10 operation, thenumber of blind decoding attempts may be 44 for the primary serving celland 32 for each of the configured and/or activated secondary servingcell(s).

Thus, as the number of carriers being aggregated increases, the numberof blind decoding attempts to be performed by the WTRU per-subframe alsoincreases. For example, if WTRU carrier aggregation is enhanced toenable aggregation of a relatively larger number of carriers (e.g., upto 32 carriers), the blind decoding burden at the WTRU couldsignificantly increase if R10 decoding rules are extended across thelarger number of carriers. From the perspective of downlink controlreception, the enhanced carrier aggregation features may increase themaximum number of blind decoding attempts. For example, the number ofblind decoding attempts may increase from 172 for the legacy system with5 carriers to 1036 for the system with 32 carriers. Such an increase indecoding complexity may result in an unacceptable increase in cost ofsystem hardware. Such an increase in decoding complexity may exceed thedesired limits of power consumption.

Further, additional complexities related to the sending of DCI via PDCCHand/or E-PDCCH transmissions for a larger number of carriers may beaddressed. For example, higher layers (e.g., radio resource control(RRC)) may configure a number of sets of serving cells for aperiodicchannel quality reporting. When sending a aperiodic channel qualityrequest, which set of higher layer configured set of serving cellsshould be used for generating the channel quality indication (CQI)report may be indicated from the value of an aperiodic channel stateinformation (CSI) field in the DCI (e.g., the value may be 2 bits).However, such a technique may be overly restrictive when a large numberof serving cells is configured.

Further, techniques may be described modifying the size of a carrierindicator field (e.g., the Release 10 size of the carrier indicatorfield may be 3 bits). The size of the carrier indicator field may or maynot be sufficient to address a larger plurality of serving cells. Forexample the size of the carrier indicator field may be insufficient toaddress up to 32 serving cells when cross-carrier scheduling may beconfigured. In another example, the current size of anActivation/Deactivation Medium Access Control (MAC) control element(e.g., the Release 10 control element payload size may be 8 bits) maynot be ideal for an increased number of available carriers. The size ofan Activation/Deactivation MAC control element may or may not besufficient to address a plurality of serving cells. For example, thesize of an Activation/Deactivation MAC control element may beinsufficient to address up to 32 serving cells.

The risk of false detection of downlink control information (DCI) mayincrease as the number of available carriers increases. An increasedrisk of false detection of DCI may result in one or more of thefollowing issues: excessive unwanted transmissions over PUCCH, spurioustransmissions over PUCCH, and/or the like.

One or more techniques may be used to lower the number of blind decodingattempts or otherwise modify downlink control channel processing toallow for reception of a greater number of DCIs to a WTRU, whilemaintaining scheduler flexibility (e.g., without overly or excessivelyimpairing such flexibility). One or more techniques may be used to lowerthe number of blind decoding attempts while still supporting an increasein the number of available scheduled shared channel transmissions.

Non-independent PDCCH/E-PDCCH processing may be used. Non-independentPDCCH/E-PDCCH processing may include techniques whereby a firstPDCCH/E-PDCCH transmission and/or the location of the firstPDCCH/E-PDCCH transmission may either explicitly or implicitly provide aWTRU with information regarding a location of a second PDCCH/E-PDCCHtransmission. Non-independent PDCCH/E-PDCCH processing may includetechniques whereby a first PDCCH/E-PDCCH transmission and/or thelocation of the first PDCCH/E-PDCCH transmission may either explicitlyor implicitly provide a WTRU with information regarding information usedto influence the blind decoding techniques for attempting to receive asecond PDCCH/E-PDCCH transmission. The second PDCCH/E-PDCCH transmissionmay be on a different carrier than the first PDCCH/E-PDCCH transmission.For example, the first PDCCH/E-PDCCH transmission may contain controlsignaling for a first serving cell and the second PDCCH/E-PDCCHtransmission may include control signaling for a second cell. In someexamples, a PDCCH/E-PDCCH may contain control signaling for a singlecell and in other instances a PDCCH/E-PDCCH may include controlsignaling for multiple cells. In another examples, a PDCCH/E-PDCCH maycontain control signaling for multiple transmissions spread acrossmultiple transmission time intervals (TTIs).

One or more DCI may contain control signaling for multiple carriers orcell and/or control signaling for multiple transmissions spread acrossmultiple transmission time intervals (TTIs). The one or more DCI may beembedded in a PDSCH transmission to a WTRU. A PDCCH/E-PDCCH, for examplea single PDCCH/E-PDCCH, may contain control signaling for multiplecarriers or TTIs. The single PDCCH/E-PDCCH may include a single DCI thatcarries control signaling for multiple carriers or TTIs. The singlePDCCH/E-PDCCH may include a plurality of DCI that carry controlsignaling for multiple carriers or TTIs. One or more, or each of the DCImay carry control signaling for a different carrier. The WTRU maydetermine that the reception of a PDCCH (e.g., a single PDCCH) mayschedule PDSCH and/or PUSCH transmissions on resources associated with aplurality of serving cells. Techniques may be used to enable PDSCHand/or PUSCH processing of multiple cells from a PDCCH and/or E-PDCCH.For example, techniques may be used to enable PDSCH and/or PUSCHprocessing of multiple cells or multiple TTIs from a single PDCCH and/orE-PDCCH.

Grouping of serving cells or TTIs may reduce overhead. The group ofserving cells may include a set of serving cells or TTIs configuredexplicitly or implicitly by higher layers. The configuration related toa serving cell may include a field indicating a group identity. Thegroup identity may be one or more of a configured number of servingcells ordered implicitly, an identified number of serving cells forwhich a WTRU reports aperiodic CSI in a given value of the aperiodic CSIfield, a given value of a carrier indicator field, and/or correspond tocertain bit position(s) within an Activation/Deactivation MAC controlelement.

Techniques are disclosed for ensuring a candidate DCI is valid for theWTRU. Robust techniques for ensuring DCI validity may reduce theprobability of a false detection by a WTRU. DCI validity determinationsmay include ensuring that a received DCI meets one or more criteria. DCIvalidity determinations may include attempting to decode DCI accordingto one or more sets of rules.

For example, the criteria for validating a DCI may include verifying thecyclic redundancy check (CRC) parity bits of the DCI. The criteria forvalidating a DCI may include verifying the CRC parity bits of the DCIafter scrambling with the appropriate RNTI. The criteria may includeverifying that one or more field of the payload is set to a validpossible value. For example, the criteria may include verifying thatevery field of the payload is set to a valid possible value. The WTRUmay perform one or more actions as a result of detecting a DCIconsidered valid according to at least a first set of criteria. The WTRUmay perform one or more actions as a result of detecting a DCIconsidered valid according to at least a first set of rules. The rulesand/or criteria may be as described herein. If, for example, the WTRUmay determine DCI validity based on a first set of criteria and/or afirst set of rules, the WTRU may attempt decoding the correspondingPDSCH. For example, if the WTRU may determine DCI validity based on afirst set of criteria and/or a first rules, the WTRU may attemptdecoding the corresponding PDSCH in case of a DCI indicating a PDSCHtransmission. If, for example, the WTRU may determine DCI validity basedon at least a second criteria and/or a second rules, the WTRU mayattempt decoding the corresponding PDSCH and/or may generate HARQ A/Nfor the corresponding PDSCH. For example, if the WTRU may determine DCIvalidity based on at least a second criteria and/or a second rules inaddition to the first criteria and/or the first rules, the WTRU mayattempt decoding the corresponding PDSCH and/or may generate HARQ A/Nfor the corresponding PDSCH. For example, if the WTRU may determine DCIvalidity based on at least a second criteria and/or a second rulesexclusive of the first criteria and/or the first rules, the WTRU mayattempt decoding the corresponding PDSCH and/or may generate HARQ A/Nfor the corresponding PDSCH. If, for example, the WTRU may determine DCIvalidity based on a second set of criteria and/or a second set of rulesas described herein, the WTRU may attempt decoding the correspondingPDSCH and/or may generate HARQ A/N for the corresponding PDSCH. Forexample, if the WTRU may determine DCI validity based on a second set ofcriteria and/or a second set of rules as described herein in addition tothe first criteria and/or the first rules, the WTRU may attempt decodingthe corresponding PDSCH and/or may generate HARQ A/N for thecorresponding PDSCH. For example, if the WTRU may determine DCI validitybased on a second set of criteria and/or a second set of rules asdescribed herein exclusive of the first criteria and/or the first rules,the WTRU may attempt decoding the corresponding PDSCH and/or maygenerate HARQ A/N for the corresponding PDSCH. If, for example, the WTRUmay detect DCI validity based on the first (set of) criteria and/or thefirst (set of) rules, but the WTRU may not determine DCI validity basedon the second (set of) criteria and/or the second (set of) rules, theWTRU may attempt decoding the corresponding PDSCH. For example, if theWTRU may detect DCI validity based on the first (set of) criteria and/orthe first (set of) rules, but the WTRU may not determine DCI validitybased on the second (set of) criteria and/or the second (set of) rules,the WTRU may attempt decoding the corresponding PDSCH.

Techniques for efficient downlink control with a large number ofcarriers and/or TTIs are described. Techniques for blind decodingreduction may include making the search space and/or aggregation levelof candidates for a first PDCCH/E-PDCCH associated with thecharacteristics of a second received PDCCH/E-PDCCH. Techniques mayinclude embedding DCI for a set of serving cells and/or TTIs in a PDSCH.DCI for a set of serving cells and/or TTIs may be included in singlePDCCH/E-PDCCH. To reduce overhead, carrier indicator fieldinterpretation may be associated with the serving cell or TTI from whichthe PDCCH/E-PDCCH containing the downlink control information isreceived, or the group of cells or TTIs to which the PDCCH/E-PDCCHcontaining the downlink control information belongs.

One or more techniques may be used to lower the number of blind decodingattempts, while maintaining scheduler flexibility (e.g., without overlyor excessively impairing such flexibility). One or more techniques maybe used to lower the number of blind decoding attempts while stillsupporting an increase in the number of available component carriers.

Non-independent PDCCH/E-PDCCH processing may be used. Non-independentPDCCH/E-PDCCH processing may include techniques whereby a firstPDCCH/E-PDCCH transmission and/or the location of the firstPDCCH/E-PDCCH transmission may either explicitly or implicitly provide aWTRU with information regarding a location of a second PDCCH/E-PDCCHtransmission. Non-independent PDCCH/E-PDCCH processing may includetechniques whereby a first PDCCH/E-PDCCH transmission and/or thelocation of the first PDCCH/E-PDCCH transmission may either explicitlyor implicitly provide a WTRU with information regarding information usedto influence the blind decoding techniques for attempting to receive asecond PDCCH/E-PDCCH transmission. The second PDCCH/E-PDCCH transmissionmay be on a different carrier/cell/TTI than the first PDCCH/E-PDCCHtransmission. For example, the first PDCCH/E-PDCCH transmission maycontain control signaling for a first serving cell and the secondPDCCH/E-PDCCH transmission may include control signaling for a secondcell. In some examples, one PDCCH/E-PDCCH may contain control signalingfor a single cell and in other instances a PDCCH/E-PDCCH may includecontrol signaling for multiple cells. When used herein, the term“PDCCH/E-PDCCH” may be interpreted as the PDCCH and/or E-PDCCH.

In an example, rather than or in addition to different PDCCH/E-PDCCHtransmissions including control information for differentcarriers/cells/TTIs, the PDCCH/E-PDCCH transmission may include controlinformation for different PDSCH and/or PUSCH for different transmissiontime intervals (TTIs), for example across a single carrier/cell/TTI.Thus, although examples described herein may be described with respectto different PDCCH/E-PDCCH transmissions including schedulinginformation for transmissions spread across multiple serving cells orcomponent carriers (e.g., in the frequency domain), the examples mayalso apply to different PDCCH/E-PDCCH transmissions that includescheduling information for transmissions spread across different TTIs(e.g., in the time domain) even if the transmissions in the differentTTIs occur on a single serving cell or component carrier.

An example of non-independent PDCCH/E-PDCCH processing may include adecoding rule whereby the set of possible candidates used in a searchspace of a first serving cell may be dependent on the outcome of PDCCHand/or E-PDCCH decoding of a second serving cell. An example ofnon-independent PDCCH/E-PDCCH processing may include a decoding rulewhereby the set of possible candidates used in a search space of a firstTTI may be dependent on the outcome of PDCCH and/or E-PDCCH decoding ofa second TTI. For example, the set of possible candidates for a firstserving cell may be dependent on one or more of the following features.

An example of non-independent PDCCH/E-PDCCH processing may includehaving one or more number and/or identity of the PDCCH/E-PDCCHcandidates in a first cell/TTI dependent or otherwise chained/linked tothe presence or absence of a PDCCH/E-PDCCH in the first servingcell/TTI. The set of possible candidates for a first serving cell may bedependent on the number and/or identity of the PDCCH/E-PDCCH candidatesin one serving cell/TTI. The number and/or identity of the PDCCH/E-PDCCHcandidates in one serving cell/TTI may be dependent or otherwisechained/linked to the presence or absence of a PDCCH/E-PDCCH in thefirst serving cell/TTI. The determination of whether the PDCCH ispresent in the first serving cell may include determining whether or notPDCCH or E-PDCCH was decoded in the second serving cell in one or moresearch spaces. For example, the WTRU may determine that a UESS of thefirst serving cell may have zero (0) candidates for decoding based on adecoding result of a second serving cell. For example, the UESS of thefirst serving cell may have zero (0) candidate if no PDCCH or E-PDCCHwas decoded in the UESS of the second serving cell. A WTRU may determinefrom the location of a DCI in a second cell/TTI that there is a number(x) of PDCCH candidate(s) for the first serving cell. The DCI may besuccessfully decoded in the UESS of the second serving cell. Thelocation of the DCI may be determined based on the starting controlchannel element (CCE) of the DCI in the UESS. The location of the DCImay be determined based on the portion of a UESS from which the DCI wasdecoded. The location of the DCI may be determined based on which UESSsearch space of a plurality of UESS for a given WTRU were used fordecoding the DCI.

An example of non-independent PDCCH/E-PDCCH processing may includehaving one or more decoding parameters used for PDCCH/E-PDCCH in a firstcell/TTI dependent or otherwise chained/linked to the decodingparameters used for of a PDCCH in a second cell/TTI. For example, thedecoding parameters of a PDCCH may include determining the aggregationlevel and/or DCI payload size of a PDCCH and/or E-PDCCH decoded in asecond cell. For instance, the aggregation level of candidates in theUESS of the first serving cell may be equal to or otherwise derived fromthe aggregation level of PDCCH and/or E-PDCCH in a second survivingcell. The DCI payload size of the first serving cell may be equal to theDCI payload size of the second serving cell.

An example of non-independent PDCCH/E-PDCCH processing may includehaving one or more decoding parameters used for PDCCH/E-PDCCH in a firstcell/TTI dependent or otherwise chained/linked to explicit signaling ina PDCCH in a second cell/TTI. The explicit signaling in a PDCCH in acell may include determining the value of a field in a PDCCH and/orE-PDCCH decoded in a second cell. For example, the aggregation level ofcandidates in the UESS of the first serving cell may be indicated (e.g.,explicitly) from a field of a DCI from a PDCCH and/or E-PDCCH decoded ina second serving cell.

The PDCCH and/or E-PDCCH decoded in a second serving cell/TTI may haveone or more of properties that indicate decoding information to be usedfor attempting to decode the PDCCH and/or E-PDCCH in a second servingcell/TTI. For example, DCI formats used for scheduling in a firstserving cell/TTI may be modified or re-interpreted in order to providethe WTRU with information or hints related to the decoding DCI includedin the PDCCH and/or E-PDCCH in a second serving cell/TTI.

A new or redefined DCI may comprise control signaling that communicates(e.g., explicitly and/or implicitly) how to reduce decoding complexity.For example, one or more specific DCI formats may be used to explicitlyand/or implicitly indicate information used to decode other DCItransmissions. The specific DCI format may be taken from legacy and/ordefined for the purpose of search space reduction. For example, the DCImay provide “decoding hints” and/or decoding parameters. To providedecoding parameters, the defined DCI format may contain a fieldindicating whether a PDCCH/E-PDCCH is present in one or more otherserving cells. To provide decoding parameters, the defined DCI formatmay contain a field indicating whether a PDCCH/E-PDCCH is present in oneor more other TTIs. For example, the DCI format may indicate whether ornot a PDCCH/E-PDCCH is present on each of the serving cells configuredfor use by the WTRU. To provide decoding parameters, the defined DCIformat may contain a field indicating the aggregation level ofPDCCH/E-PDCCH for one or more other serving cells. To provide decodingparameters, the defined DCI format may contain a field indicating theaggregation level of PDCCH/E-PDCCH for one or more other TTIs. Forexample, the DCI format may indicate the aggregation level ofPDCCH/E-PDCCH for each of the serving cells configured for use by theWTRU. The aggregation level of PDCCH/E-PDCCH may be possibly for one ormore DCI payload size. For example, the aggregation level ofPDCCH/E-PDCCH may be for each possible DCI payload size.

The control signaling that communicates (e.g., explicitly and/orimplicitly) how to reduce decoding complexity may explicitly orimplicitly indicate to which cells the decoding hints are applicable.For example, the DCI that may provide “decoding hints” and/or decodingparameters may include control signaling such as a sequence of one ormore bits. At least one such sequence may be used for one or more cellof a group of one or more cells. For example, at least one such sequencemay be used for each cell of a group of one or more cells. For example,the control signaling may be structured using a plurality of thesequences of one or more bits. The sequences may be orderlyconcatenated. For example, the sequences may be orderly concatenated toincrease value of the serving a cell identity associated to an (e.g.,each) applicable cell. The cell identity associated to an (e.g., each)applicable cell may be a servCellID configured by L3.

The DCI that may provide “decoding hints” and/or decoding parameters maybe applicable to one or more cells and/or one or more TTIs. For example,the DCI may be applicable to an individual cell, a groups of cells,and/or all cells of the WTRU and/or may be applicable one or more TTIs.For example, the group of cells to which DCI is applicable to mayinclude a cell (e.g., at least one of all cells) of the WTRU, all cellsof a configured group of cells (e.g., a cell group (CG), if configuredwith dual connectivity), and cells configured for example by L3/RRC toform the configuration. The cells to which the DCI is applicable to mayinclude activated cells of the WTRU's configuration. For example, thecells to which the DCI is applicable to may comprise activated cells ofthe WTRU's configuration. The cells to which the DCI is applicable tomay include cells that are in the activated state at a specific time. Insome examples, the cells to which the DCI is applicable to may includethe cells that are in the activated state at a specific time but may notinclude cells that are not activated and/or deactivated at that time.For example, the cells to which the DCI is applicable to may includecells that are in the activated state at a specific time in the subframein which the control signaling may be successfully decoded. The cells towhich the DCI is applicable to may include cells that are in theactivated state at a specific time in the TTI in which the controlsignaling may be successfully decoded. The cells to which the DCI isapplicable to may include cells that are in the activated state at aspecific time in a subframe preceding the subframe in which the controlsignaling may be successfully decoded. The cells to which the DCI isapplicable to may include cells that are in the activated state at aspecific time in a TTI preceding the TTI in which the control signalingis decoded.

A sequence of bits in a first DCI may be used to indicate what decodinghint/assumption should be used for attempting to decode a second DCIand/or to indicate which serving cell(s) and/or TTI(s) the decoding hintis applicable to. The sequence of bits in the first DCI may include oneor more of a Presence flag (P), an Aggregation Level (AL), a size ofDCI(s), a Delay Offset (DO), and/or the like.

For example, the sequence of bits in a DCI may include a Presence flag(P). The presence flag may be a bit (e.g., a single bit) that mayindicate whether or not a PDCCH is present for the WTRU in another cell.For example, the WTRU may determine whether decoding attempts for aPDCCH in a second cell should be performed based on whether the presenceflag in the first DCI of the first cell indicates whether or not thePDCCH is not present.

The sequence of bits in a first DCI that provides decoding hints for asecond DCI may include an Aggregation Level (AL). The AL may include oneor more bits. For example, one (1) bit may indicate one of two (orpossibly more) sets of possible aggregation levels (e.g., 1, 2 or 4, 8)to use for decoding the second DCI. In an example, two (2) bits mayindicate the AL (e.g., 1, 2, 4 or 8) for the second DCI in case finergranularity and/or a larger amount of values may be used. The meaning ofa field containing an AL may depend on the configuration of the firstserving cell. For example, the meaning of a field containing an AL maybe a function of the configuration of the first serving cell.

The sequence of bits in a first DCI that provides decoding hints for asecond DCI may include a size of one or more other DCI(s). For example,the first DCI may explicitly indicate the size of the second DCI. In anexample, the sequence of bits indicating the size of the second DCI mayindicate one (or more) sizes from a plurality of possible sizes. Asingle bit may be used to indicate one two possible sizes for DCIcandidates.

The sequence of bits in a first DCI that provides decoding hints for asecond DCI may include a Delay Offset (DO). For example, the DO mayinclude timing information for the applicability of the controlinformation. For example, the DO may indicate that the second DCI willbe in a subsequent TTI. The DO may be a single bit that may indicatewhether the signaling pertains to the current subframe or to the nextsubframe.

The sequence of bits may be associated with one or more codepoints. Thecodepoints may combine one or more indicators communicated by theaforementioned sequence of bits. For example, “000” may indicate anabsence of PDCCH for a given cell or for a group of cells. “001” mayindicate presence of a PDCCH with AL=1, etc.

The WTRU may determine the “first” carriers or TTIs(s) to which thecontrol signaling may be applicable. The “first” carriers or TTIs(s) towhich the control signaling may be applicable may be one or more cell ofa group of one or more cells. The one or more cell of a group of one ormore cells may be a subset of all cells. The “first” carriers or TTIs(s)to which the control signaling may be applicable may be one or more TTIof a group of one or more TTIs. The one or more TTI of a group of one ormore TTIs may be a subset of all TTIs. For example, a DCI may containcontrol signaling for a single group of cells. When the DCI containscontrol signaling for a single group of cells, the WTRU may determine towhat group of one or more cell(s) the control signaling may beapplicable. For example, the determination may be based on one or moreof the following factors: a cell associated with the PDCCH of the DCI,RNTI that may be used to decode the PDCCH of the DCI, a location of thePDCCH of the DCI, a search space associated with the received DCI, a CRCpolynomial used to decode the PDCCH of the DCI, and an indication (e.g.a bitmap) inside the DCI.

The WTRU may determine for what group of one or more cell(s) the controlsignaling may be applicable based on a cell associated with the PDCCH ofthe DCI. For example, the cell associated with the PDCCH of the DCI mayindicate a same cell or same group of cells. The WTRU may determine thatthe control signaling is applicable to cell(s) of the same group as thegroup of the cells on which the WTRU received the PDCCH of the DCI. TheWTRU may determine that the received control signaling is applicable tocell(s) that are scheduled by the cell on which the PDCCH is received.

The WTRU may determine to what group of one or more cell(s) the controlsignaling may be applicable based on RNTI that may be used to decode thePDCCH of the DCI. For example, the WTRU may be configured with aplurality of RNTI(s) (e.g., one for each group of cells). The WTRU maydetermine that the received control signaling is applicable to one ormore cell(s) (e.g., a group of cells) as a function of the RNTI that maybe used to successfully decode the PDCCH.

The WTRU may determine to what group of one or more cell(s) the controlsignaling may be applicable based on the location of the PDCCH of theDCI (e.g., in the UESS, in the CSS, etc.). For example, the WTRU maydetermine that the control signaling is applicable to one or morecell(s) (e.g. a group of cells) as a function of a control channelelement (CCE) of the DCI. The CCE of the DCI may be the first CCE forthe received DCI. For example, CCEs may be organized using anumerological sequence (e.g., where the first CCE of a SS is #0, thesecond CCE corresponds to #2, etc.). The WTRU may determine that thereceived control signaling is applicable to the group of cellsassociated with the numerological value (or range thereof) correspondingto the first CCE of the DCI. The WTRU may determine that the receivedcontrol signaling is applicable to the group of cells associated withthe range of numerological value corresponding to the first CCE of theDCI. The WTRU may determine that odd indices may indicate a first groupof cells. The WTRU may determine that even indices may indicate a secondgroup of cells.

The WTRU may determine for what group of one or more cell(s) the controlsignaling may be applicable based on the search space associated withthe received DCI. For example, the WTRU may determine that the controlsignaling is applicable to one or more cell(s) (e.g., a group of cells)as a function of the search space of the DCI that carries the controlsignaling. The WTRU may determine that the received control signalingmay apply to decoding in the same search space for the one or more cellsto which the control signaling is applicable. For example, the controlsignaling may be applicable to the one or more cells as a function ofthe search space of the received DCI. The search space may be used, forexample, by CSS or UESS, and the received DCI may be associated with theCSS or UESS respectively. For example, the WTRU may determine that thereceived control signaling applies to a specific group of cellsassociated with a given UESS or a portion of the UESS when the WTRUdetermines that the DCI is received in the concerned UESS.

The WTRU may determine for what group of one or more cell(s) the controlsignaling may be applicable based on the CRC polynomial that may be usedto decode the PDCCH of the DCI. For example, the WTRU may be configuredwith one or more CRC polynomials. The one or more CRC polynomials mayinclude the number of bits in the DCI applicable for the CRCcomputation. The one or more CRC polynomials may be associated with aspecific DCI type. The WTRU may perform additional decoding attempt(s)of a DCI of a specific size using the polynomials and/or thecorresponding number of bits (e.g., the last 16 bits). The WTRU maydetermine that the DCI is a format that includes the control signaling.For example, the WTRU may determine that the DCI is a format thatincludes the control signaling (e.g. decoding hints) upon successfuldecoding. The control signaling ma The one or more CRC polynomials yinclude decoding hints. The polynomial may be associated with a group ofcell(s). The WTRU may determine that the control signaling is applicableto the corresponding group of cell(s). For example, the WTRU may use theconcerned polynomial and determine that the control signaling isapplicable to the corresponding group of cell(s), upon successfuldecoding of the PDCCH.

The WTRU may determine to what group of one or more cell(s) the controlsignaling may be applicable based on an indication (e.g., a bitmap)inside the DCI. For example, the WTRU may determine that the controlsignaling is applicable to one or more cell(s) (e.g. a group of cells)as a function of an indication inside a bitmap arrangement in the DCI.

One or more DCI may contain control signaling for multiplecarriers/cells and/or multiple TTIs. The one or more DCI may be embeddedin a PDSCH transmission to a WTRU. A PDCCH/E-PDCCH, for example a singlePDCCH/E-PDCCH, may contain control signaling for multiple carriers/cellsand/or multiple TTIs. The single PDCCH/E-PDCCH may include a single DCIthat carries control signaling for multiple carriers/cells and/ormultiple TTIs. The single PDCCH/E-PDCCH may include a plurality of DCIthat carry control signaling for multiple carriers/cells and/or multipleTTIs. One or more of the DCI may carry control signaling for a differentcarrier/cell/TTI. For example, each of the DCI may carry controlsignaling for a different carrier/cell/TTI. The WTRU may determine thatthe reception of a PDCCH (e.g., a single PDCCH) may schedule PDSCHand/or PUSCH transmissions on resources associated with a plurality ofserving cells of the WTRU's configuration. Techniques may be used toenable PDSCH and/or PUSCH processing of multiple cells from a PDCCHand/or E-PDCCH. For example, techniques may be used to enable PDSCHand/or PUSCH processing of multiple cells from a single PDCCH and/orE-PDCCH.

Techniques used to enable PDSCH and/or PUSCH processing of multiplecarriers/cells/TTIs from a single PDCCH and/or E-PDCCH may includeembedded DCI for multiple carriers/cells/TTIs. An embedded DCI may referto a DCI that is included in or embedded in a PDSCH transmission. A DCImay be transmitted inside RBs used for a PDSCH transmission to a WTRU ina given subframe. One or more DCI messages may be contained in the RBsused for PDSCH. DCI messages contained inside RBs used for PDSCHtransmission to a WTRU may refer to the same subframe and/or another,for example later occurring subframe. DCI transmitted inside RBs usedfor a PDSCH transmission may be destined for the WTRU that is theintended receiver of data or control information in the PDSCH. DCItransmitted inside RBs used for a PDSCH transmission may be destined foranother WTRU that is not the intended receiver of the PDSCHtransmission. In scenarios in which multiple DCIs may be transmitted inRBs used for PDSCH transmission in any of the aforementioned techniques,these multiple DCI messages may be separately processed/mapped totime/frequency resources. In scenarios in which multiple DCIs may betransmitted in RBs used for PDSCH transmission in any of theaforementioned techniques, these multiple DCI messages may beconcatenated/jointly channel coded.

An embedded DCI for multiple carriers/cells/TTIs may be multiplexed withthe Transport Channel bits prior to mapping of the modulation symbols totime/frequency resources. For example, a DCI may be multiplexed with theTransport Channel bits prior to mapping of the modulation symbols totime/frequency resources when transmitted in resource blocks (RBs) thatmay be used for PDSCH transmission. A concatenated string of bitsobtained from transport block (TB) bits and/or DCI bits may be processedby the transmitter. For example, a CRC for an N bit TB containing dataand/or a CRC for an M bit DCI containing control information may beseparately determined. One part, or both parts, may be separatelychannel coded. One part, or both parts, may be separately channel codedusing Turbo coding for the TB and/or Convolutional Coding for the DCI.One, or both, channel coded segments may be concatenated, interleaved,processed, and/or mapped to PDSCH time/frequency resources in a subframefor transmission. A receiving WTRU may determine modulation and codingscheme (MCS), TB size, and/or RB allocation from a DCI announcing thePDSCH. The receiving WTRU may process the received RBs. For example, thereceiving WTRU may process the received RBs according to a firsthypothesis that DCI is contained in the PDSCH. The receiving WTRU mayprocess the received RBs according to a second hypothesis that no suchDCI is present.

An embedded DCI for multiple carriers/cells/TTIs may be multiplexed withPDSCH onto a set of determined modulation symbols and/or channel codedbit positions in the set of time/frequency resources used for PDSCH. Forexample, a DCI may be multiplexed with PDSCH when transmitted in RBsthat may be used for PDSCH transmission. DCI and/or PDSCH may beseparately processed based on one or more of CRC, channel coding,rate-matching, and/or the like. Channel coded DCI bits may be mapped toa set of resource elements (REs) that may be part of the RBs used forPDSCH. PDSCH mapping may or may not be adjusted accordingly in terms ofrate-matching.

An embedded DCI for multiple carriers/cells/TTIs may be mapped startingfrom possible starting symbol and/or bit positions. For example, a DCImay be mapped starting from possible starting symbol and/or bitpositions when transmitted in RBs that may be used for PDSCHtransmission. The starting symbol and/or bit positions may be fixedvalues and/or sets of values. The starting symbol and/or bit positionsmay be obtained from a function that may involve varying parameters. Thevarying parameter may be one or more of Cell ID, WTRU ID, subframe ortimeslot index, RB number, component carrier number for which the DCImay be intended, and/or the like. A set of potentially differentstarting positions may be allowed, for example if multiple DCIs aretransmitted, among other scenarios.

An indication may be transmitted to a WTRU. The indication may allow theWTRU to determine that an embedded DCI for multiple carriers/cells/TTIsis transmitted in RBs used for PDSCH. The indication may refer to adetermined set of RBs (e.g., only such RBs). The indication may refer toa set of candidate RBs. The indication may refer to one or more, or all,RBs containing channel coded data in a subframe. The indication mayrefer to a given subframe. The indication may refer to a given TTI.

For example, the DCI on PDCCH and/or EPDCCH announcing the PDSCH maycontain an indication in the form of a bit flag and/or a codepointsetting that DCI is contained in the announced PDSCH. This may allow theWTRU to configure its receiver accordingly and/or start PDSCH decoding.

For example, a sequence of phase value of time/frequency symbols may beadjusted to carry an indication for DCI transmitted in RBs that may beused for PDSCH. The time/frequency symbols used for indicating the phasevalue may be known to the WTRU. A WTRU may determine that the DMRSsymbols of RBs it is demodulating indicates a first configuration. AWTRU may configure its receiver to decode for presence of PDSCH. TheWTRU may configure it receiver to decode for presence of DCI and/orPDSCH. For example, the WTRU may configure it receiver to decode forpresence of DCI and/or PDSCH when the WTRU determines a secondconfiguration through the DMRS symbols. Different phase values and/orcode settings may be used for the DMRS based indication.

A WTRU may implement a detection procedure. Through the detectionprocedure, the WTRU may determine for a set of RBs whether a DCI ispresent or not. The RBs may be used by the PDSCH transmission. The WTRUmay or may not be an intended WTRU for the PDSCH transmission. The WTRUmay implement the detection procedure, when the DCI may be destined forthe same WTRU for which the PDSCH is intended. The WTRU may implementthe detection procedure, when the DCI may be destined for a second WTRU(e.g., the DCI is included in a PDSCH transmission sent to anotherWTRU).

For example, when DCI is transmitted in RBs used for PDSCH, the possiblestarting symbol and/or bit positions may correspond to a deterministicset. In a given subframe, a WTRU may demodulate and/or determine for oneor more possible starting position whether the DCI is detected. Forexample, the WTRU may demodulate and/or determine for each of a set ofpossible starting positions whether DCI is detected. Where the DCI maybe detected, the WTRU may configure its receiver according to thereceived DCI. The DCI transmitted in RBs used for PDSCH may be encodedin a way that is directed to intended receiving WTRUs. For example, theDCI may be encoded in a way that intended receiver WTRUs may correctlydecode the DCI but the DCI is not decodable by WTRUs for which the DCIis not intended. An example may be that CRC may be masked with WTRU RNTIvalues. DCI may be encoded such that any receiver WTRU may determinecorrect detection, yet may still discard and/or further process thereceived DCI by determining an identifier from the DCI.

A WTRU may determine outcomes of DCI processing for the embedded DCI formultiple carriers/cells/TTIs. For example, a WTRU may determine outcomesof DCI processing when a DCI is transmitted in RBs used for PDSCHtransmission. The WTRU may further process and/or generate feedback tothe transmitter (e.g., eNB) based on the outcomes of the DCI decoding.Feedback may correspond to Ack/Nack feedback, channel measurements,counters, and/or reportable error statistics and/or representative errorstatistics. Channel measurements may include signal-to-noise ratio (SNR)and/or derived values.

The WTRU may generate, store, and/or report statistics related to thesuccess/failure of receiving DCI in the PDSCH (and/or on a downlinkcontrol channel). Outcomes of DCI processing for DCI transmitted in RBsmay be processed and/or recorded in one or more of the followingstatistics: decoding successful, decoding not successful, number ofcorrect decodes over a period, number of no decodes over a period, thesignal-to-noise ratio (or equivalent or indexed as a function thereof)for symbols, and/or bit positions where DCI may be contained.

Link adaptation may be implemented on the transmitter side, perhaps forexample in the presence of feedback on performance for DCI transmittedin RBs used for PDSCH. For example, a transmitter may decrease thecoding rate for DCI in the presence of feedback on performance for DCItransmitted in RBs used for PDSCH. The decreased coding rate for DCI mayallow for more robust transmissions. For example, when a WTRU reportsmultiple decoding and/or missed detection events, the decreased codingrate may allow for more robust transmissions. Another exemplar linkadaption is that the transmitter may chose smaller DCI sizes to improveupon link robustness.

For example, a WTRU configured to decode for presence of DCI transmittedin RBs used for its PDSCH transmissions may report to the eNB the numberof DCI that it was able to successfully decode. The WTRU may report tothe eNB at regular time intervals. The WTRU may report to the eNB whenpolled by the eNB about the number of successful decoded DCI. The eNBmay know the number of DCI that it transmitted to that WTRU. The eNB maydetermine a DCI error rate from the reported value. The eNB may adjustlink settings.

Techniques used to enable PDSCH and/or PUSCH processing of multiplecarriers/cells/TTIs from a single PDCCH and/or E-PDCCH may include asingle DCI or a plurality of DCIs in a PDCCH and/or E-PDCCH. A singleDCI or a plurality of DCIs in a PDCCH and/or E-PDCCH (may referred toPDCCH in some examples hereafter, but these examples may also apply tothe E-PDCCH) may provide scheduling information for multiple servingcells or TTIs. A WTRU may receive PDCCH and/or E-PDCCH containingscheduling information for a plurality of cells or a plurality of TTIs.For example, a single PDCCH and/or E-PDCCH may contain schedulinginformation for a plurality of cells or a plurality of TTIs. The singlePDCCH and/or E-PDCCH may contain one DCI comprising schedulinginformation for a plurality of cells or a plurality of TTIs. The singlePDCCH and/or E-PDCCH may contain a plurality of DCIs. For example, eachone of the plurality of the DCI may contain scheduling information for adifferent cell or TTI.

DCI contained in a PDCCH for multiple cells or TTIs may include using asingle DCI for multiple cells or TTIs. The WTRU may receive a PDCCH thatmay include scheduling information applicable to transmissionsassociated to a plurality of cells of the WTRU's configuration. ThePDCCH may include a single DCI. The transmissions may be a downlinktransmission received on PDSCH and/or an uplink transmission on PUSCH.DCI may indicate scheduling information for a plurality of transportblocks. DCI may indicate scheduling information for a transport blockwhich spans over the plurality of cells or TTIs.

For example, a single DCI may correspond to multiple TBs. One or more ofthe multiple TBs may be associated with a different cell or TTI. Forexample, the WTRU may determine that a DCI indicates schedulinginformation for a plurality of transport blocks (TBs), and each TB maybe associated with a different cell or TTI. The WTRU may determinetransmission parameters for one or more TBs. For example, the WTRU maydetermine the transmission parameters for each of the TBs. How thetransmission parameters are granted or assigned to the TBs may vary.

How the transmission parameters are granted or assigned to the TBs maybe that the DCI may grant or assign same and valid scheduling parametersto one or more TBs. For example, each TB associated with a cell or a TTImay be granted the same scheduling parameters. The DCI may include a setof scheduling parameters. The scheduling parameters may comprise one ormore of PRBs, MCS, redundancy version (RV), hybrid automatic repeatrequest (HARQ) process ID, and/or the like. The scheduling parametersmay be common to each of the cells and/or TTIs being scheduled orseparate sets of scheduling parameters may be provided for each celland/or TTI being scheduled. For example, the DCI may include a singleset of scheduling parameters. The WTRU may use the same set ofparameters for one or more different cells. For example, the WTRU mayuse the same set of parameters for all TBs. Some or all of thescheduling parameters may translate into different sets of transmissionparameters. For example, the number of PRBs may additionally be afunction of the bandwidth of the concerned cell.

For example, the DCI may grant or assign one or more different set ofscheduling parameters to one or more TBs. For example, each TBassociated with a cell or a TTI may be granted one or more different setof scheduling parameters.

The DCI may include additional scheduling information. For example, theDCI may include the list of applicable cells or applicable TTIs. The DCImay include the list of applicable cells or applicable TTIs using abitmap for a group of cells or a group of TTIs. The list may identifythe one or more secondary carriers/cells/TTIs. For example, the list mayidentify the secondary cells or TTIs when the WTRU may not explicitly orimplicitly determine the applicable cells using other techniquesdescribed herein. For example, the DCI may include alternative valuesfor one or more of PRB, MCS, RV, and/or a HARQ process identity for oneor more of the second cells or TTIs.

How the transmission parameters are granted or assigned to the TBs maybe that the DCI may grant or assign same and valid scheduling parametersto a single TB. A single transmission (e.g., a single TB) may spreadacross resources that may be associated with one or morecarriers/cells/TTIs. For example, a single DCI may correspond to asingle TB spanning across different cells and/or spanning acrossmultiple TTIs. The WTRU may determine that a DCI indicates schedulinginformation for a single TB. The TB may be transmitted on one or moredifferent sets of physical resources (e.g., physical resources blocks(PRBs)). One or more set of physical resources may be associated withdifferent serving cells or different TTIs. For example, each set ofphysical resources may be associated with different serving cells ordifferent TTIs. The WTRU may determine that the TB may be transmitted ondifferent and/or disjoint sets of PRBs.

A TB may be mapped to PDSCH and/or PUSCH in one or more serving cells orTTIs. Modulated symbols for the transport block may be mapped toresource elements from the one or more serving cells or TTIs.

For example, the WTRU may determine the transmission parameters for thesingle TB according to one or more of the following techniques.

The one or more techniques may include an example of procedure where theDCI may include a single set of scheduling parameters (e.g., PRBs, MCS,RV, and/or HARQ process ID, etc). The WTRU may use the parameterssimilar to legacy, perhaps except for the PRB. The WTRU may determineone or more different sets of PRBs associated with one or more cells.For example, the WTRU may determine one or more different sets of PRBsassociated with each cell. The WTRU may determine one or more differentsets of PRBs associated with one or more cells by applying the parameterindependently for one or more cells. The WTRU may determine one or moredifferent sets of PRBs associated with one or more cells by applying theparameter independently for each cell. The WTRU may consider the sum ofone or more PRBs. For example, the WTRU may consider the sum of allPRBs. The WTRU may derive the TB size using similar methods as forlegacy methods. The parameters related to the PRBs may translate intoone or more different sets of transmission parameters. For example, thenumber of PRBs may additionally be a function of the bandwidth of theconcerned cell or TTI.

The DCI may include one or more different sets of scheduling parameters(e.g. PRBs, MCS, RV, and/or HARQ process ID, etc.) for one or moretransmission parameters. For example, the DCI main include signaling forPRBs independently for one or more applicable cell. For example, the DCImain include signaling for PRBs independently for each applicable cell.

Techniques used to enable PDSCH and/or PUSCH processing of multiplecells from a single PDCCH and/or E-PDCCH may include using a pluralityof DCIs and transmissions for multiple cells or TTIs. DCI contained in aPDCCH for multiple cells or TTIs may include using a plurality of DCIsand transmissions for multiple cells or TTIs. The multiple DCIs may beseparately and/or jointly encoded in a given PDCCH and/or E-PDCCHtransmission. For example, the WTRU may receive a PDCCH that may includescheduling information applicable to transmissions associated with aplurality of cells or TTIs of the WTRU's configuration. The PDCCH mayinclude a plurality of DCIs.

A plurality of DCI may correspond to multiple TBs. One or more TB may bein different cells/TTIs. For example, each TB may be in a different cellor TTI. The WTRU may determine that a PDCCH may include a plurality ofDCIs. One or more DCI may include scheduling information fortransmissions associated with a different cell of the WTRU'sconfiguration. For example, each DCI may include scheduling informationfor transmissions associated with a different cell of the WTRU'sconfiguration. The PDCCH may include cross-carrier schedulinginformation in order to indicate which cells the DCI is applicable to.The PDCCH and/or E-PDCCH may include cross-TTI scheduling information inorder to indicate which TTIS the scheduling information is applicableto. The PDCCH may include a single CRC. For example, the PDCCH mayinclude a single CRC appended after the plurality of DCIs. PDCCHdecoding may be performed on the concatenation of the plurality of DCIs.

For one or more of the techniques described herein, the controlsignaling and/or parameters associated with a given cell or TTI of theWTRU's configuration may be present. For example, for one or more of thetechniques described herein, the control signaling and/or parametersassociated with a given cell or TTI of the WTRU's configuration may bepresent in the absence of a transmission using resources of a cell orTTI. The cell may be the concerned cell and/or group of cell(s) ifapplicable. The TTI may be the concerned TTI and/or group of TTI(s) ifapplicable. The WTRU may determine that the control signaling and/orparameters associated with a given cell or TTI of the WTRU'sconfiguration may be present when it receives a PDCCH according to a oneor more of the following scenarios. In one of the scenarios, the WTRUmay determine that the signaling indicates that the resources of thecell (DL and/or UL) are not being scheduled by the concerned PDCCH. Thesignaling, if any, may be used to indicate whether or not the PDCCH isapplicable to a specific cell, for example using a bitmap. In one of thescenarios, the control signaling and/or parameters associated to a givencell of the WTRU's configuration may be present. The WTRU may determinethat the cell is in the inactive state. This scenario may be applicableto scheduling for downlink transmissions and/or uplink transmissions forthe associated cell. In one of the scenarios, the control signalingand/or parameters associated to a given cell of the WTRU's configurationmay be present. The WTRU may determine that the cell may not be uplinktime-aligned. This scenario may be applicable to scheduling for uplinktransmissions for the associated cell, for example only for theassociated cell. In one of the scenarios, the control signaling and/orparameters associated to a given cell of the WTRU's configuration may bepresent. The WTRU may determine that control signaling is received.Control signaling may further indicate for what transmissions (and/orcell(s)) the WTRU may be expected to generate a HARQ A/N report. TheWTRU may determine that no HARQ A/N report might be expected for a givencell, such that it may additionally determine that no (e.g., downlinkonly) transmission is being scheduled for the concerned cell. In one ofthe scenarios, the control signaling and/or parameters associated to agiven cell of the WTRU's configuration may be present. The WTRU maydetermine that cell-specific transmission parameters for the concernedcell(s) may be absent and/or set to a specific value (e.g. zeroed). Inone of the scenarios, the control signaling and/or parameters associatedto a given cell of the WTRU's configuration may be present, in anycombination of the aforementioned scenarios where scheduling informationfor uplink and/or downlink transmissions and/or for a plurality of cellsmay be available or provided.

Techniques used to enable PDSCH and/or PUSCH processing of multiplecarriers/cells/TTIs from a single PDCCH and/or E-PDCCH may comprisecompressing resource allocation information for multiplecarriers/cells/TTIs. For example, certain subsets of fields in DCIinformation may include differentiated information for multiple cellsand/or DCIs and other cells may include common information. For example,the resource allocation information may indicate separate informationfor each cell and/or TTI being scheduled and other fields such as MCSmay be common across the multiple cells being scheduled. The fields thatinclude differentiated information for multiple cells may be jointlyencoded or otherwise compressed in order to reduce the number of bitsused. Resource allocation information may be compressed for one or morecarriers/cells/TTIs. For example, resource allocation information may becompressed for multiple serving cells or multiple TTIs. Compressingresource allocation information may be achieved through one or more ofthe following techniques: one or more fields from one or more DCIs of aPDCCH and/or E-PDCCH may contain the resource allocation information forPDSCH and/or PUSCH; a pre-defined set of RBs may be assigned to themultiple serving cells or TTIs; and a subset of cells or TTIs may beidentified and mapped to a predefined sets of RBs or a sets of RBsconfigured by higher layers.

The WTRU may determine resource allocation information for PDSCH and/orPUSCH in one or more cells or TTIs from at least one field that may bereceived in one or more DCIs of a PDCCH and/or E-PDCCH. The WTRU maydetermine resource allocation information for PDSCH and/or PUSCH in aplurality of cells or TTIs from at least one field that may be receivedin one or more DCI's of a PDCCH and/or E-PDCCH. The combined size of theat least one field may be reduced. For example, the combined size of theat least one field may be significantly reduced, comparing with a sizeof field through the reuse of existing techniques. The existingtechniques may allocate portions of resources on a per-cell basis.Downlink control overhead may be minimized through the reduction ofcombined size of field. It may or may not be useful or efficient for thenetwork to allocate portions of resources over multiple cells when alarge number of carriers/cells/TTIs may be aggregated.

The WTRU may determine that at least one of pre-defined sets of RB's maybe allocated for at least one cell. For example, the WTRU may determinethat at least one of pre-defined sets of RB's may be allocated for atleast one cell based on an indication of the at least one cell. Apre-defined set of RB's may comprise all RBs of the cell, no (zero) RB,and/or a subset of RBs configured by higher layers. The DCI may thenindicate that the pre-defined sets of RBs (e.g., one of a set ofpotential predefined RB allocations) has been allocated for the WTRUusing reduced size signaling (e.g., rather than a full sized legacy DICformat). For example, the subset of RBs configured by higher layers maybe on a per cell basis. Signaling overhead may be reduced for resourceallocation when, for a subset of cells or TTIs, a few bits may be usedto indicate the pre-defined resource (e.g., rather than including thefull scheduling information in the DCI). Indicating a detailed RBallocation for each cell or TTI scheduled by the PDCCH and/or E-PDCCHmay require >˜20 bits while referring to predefined allocations may beperformed using just a few bits.

The WTRU may determine a set of cells or TTIs for which a pre-definedset of RBs may be allocated for one or more cells or TTIs based on atleast one field received in the DCI. The WTRU may determine a set ofcells or TTIs for which a pre-defined set of RB's may be allocated foreach of the cells or TTIs based on at least one field received in theDCI. The WTRU may determine a set of cells which pre-defined set of RB'smay be used for one or more cells, based on at least one field receivedin the DCI. The WTRU may determine a set of cells which pre-defined setof RB's may be used for each of the cells based on at least one fieldreceived in the DCI. For example, one field may indicate for one or morecell or TTI whether and/or which one of the pre-defined sets of RB's maybe allocated for the cell or TTI. One field may indicate for each cellor TTI whether and/or which one of the pre-defined sets of RB's may beallocated for the cell. For instance, if two bits are used for each cellin this field, one out of a number of four possible values may indicatethat a detailed RB allocation (e.g., as in existing system) may beprovided for the cell (e.g., in a subsequent field). The three othervalues may each indicate one of the set of pre-defined set of RBs.

For example, a first field may indicate the subset of cells or TTIs forwhich a pre-defined set of RBs may be allocated. A first field mayindicate the subset of cells or TTIs for which a detailed RB allocationmay be provided. One or more possible value of the first field maycorrespond to a subset of cells or cell groups. The subset of cells maycomprise a single cell. For example, each possible value of the firstfield may correspond to a subset of cells or cell groups. A value of thefirst field and a subset of cells may be mapped. The mapping may beconfigured by higher layers. The mapping may be pre-defined. A secondfield may indicate for one or more subsets of cells indicated in thefirst field, which of the set of pre-defined RB's may be allocated. Asecond field may indicate, for each subset of cells indicated in thefirst field, which of the set of pre-defined RB's may be allocated. Forexample, the technique discussed herein may be used when two sets ofpre-defined RB's may be pre-defined. The second field may use one bitper cell (perhaps e.g., only one bit per cell) indicated in the firstfield.

The WTRU may determine the subset of RBs for at least one cell based onat least one RB assignment field. For example, the WTRU may determinethe subset of RBs for the at least one cell based on at least one RBassignment field if the WTRU determines that a pre-defined set of RBs isnot allocated for the at least one cell. One or more assignment fieldmay indicate a subset of RBs for at least one cell. For example, each RBassignment field may indicate a subset of RBs for at least one cell. Theorder of the RB assignment fields may be based on a cell index and/orcell identity among the subset of cells for which a pre-defined set ofRB's might not be allocated. The order of the RB assignment fields maybe based on a cell index and/or cell identity among the subset of cellsfor which a pre-defined set of RB's may not be allocated. One or moreassignment field may indicate a subset of RBs across more than one cellor TTI. Each RB assignment field may indicate a subset of RBs acrossmore than one cell or TTI. For example, the field may be interpretedsuch that a bandwidth corresponds to the sum of the bandwidths of themore than one cell or TTI.

For example, a PDCCH/E-PDCCH may schedule PDSCH and/or PUSCH for four(4) cells. There may be two (2) pre-defined sets of RB's: “No RB” and“All RB's”. In every assignment, three (3) out of the 4 cells or TTIsmay be allocated one (1) of the pre-defined sets. One (1) cell or TTImay be allocated according to a RB assignment field.

In such scenario, the set of fields for the RB allocation of all cellsmay include the following: one 2-bit field, one 3-bit field, one RBallocation field, and padding bits. The 2-bit field may indicate which 3out of the 4 cells may be allocated a pre-defined set of RBs. Forexample, “00”, “01”, “10” and “11” may indicate that cells (2,3,4),(1,3,4), (1,2,4) and (1,2,3) are allocated a pre-defined set of RB'srespectively, and correspondingly that cell 1, 2, 3 or 4 respectivelymay be allocated according to a RB assignment field.

The set of fields for the RB allocation of all cells may include one3-bit field. The 3-bit field may indicate, for each of the 3 cells thatare allocated a pre-defined set of RBs, if the pre-defined set is “NoRB” or “All RB's”.

The set of fields for the RB allocation of all cells may include atleast one RB allocation field for the 1 cell that is not allocated apre-defined set of RB. The size of this field may correspond to thenumber of RB's (e.g., carrier bandwidth) for the cell.

The set of fields for the RB allocation of all cells may include paddingbits. The padding bits may ensure that the total number of bits for theaforementioned fields may be set to a known value.

Techniques used to enable PDSCH and/or PUSCH processing of multiplecarriers/cells/TTIs from a single PDCCH and/or E-PDCCH may comprise oneor more ways in which a WTRU decodes the PDCCH that contains the controlsignaling described herein. For example, the WTRU may determine that aPDCCH contains any of the control signaling described herein (e.g. aPDCCH format/type and/or a DCI format/type) using differentiationmethods similar to those described herein for the reception of thecontrol information.

The WTRU may determine the type of the PDCCH (and/or DCI) as a functionof one or more factors described herein, including a configurationaspect. For example, the WTRU may determine whether or not the controlsignaling may occur on the PDCCH of a given cell, perhaps if the WTRU isconfigured with the functionality.

The WTRU may determine the type of the PDCCH (and/or DCI) as a functionof a RNTI used to decode a PDCCH. For example, the WTRU may determinethat the control signaling is included in the PDCCH as a function of theRNTI used to successfully decode the PDCCH candidate. For example, theWTRU may be configured with a specific RNTI value for the techniques.

The WTRU may determine the type of the PDCCH (and/or DCI) as a functionof a location of the PDCCH in the search space. For example, the WTRUmay determine from the location (e.g. starting CCE of the DCI in aspecific range and/or in a specific search space and/or portion thereof)that the control signaling is included in the PDCCH.

The WTRU may determine the type of the PDCCH (and/or DCI) as a functionof a search space. For example, the WTRU may determine that the controlsignaling is included in the PDCCH as a function of the search space inwhich the PDCCH is decoded. For example, the WTRU may determine that anyPDCCH receive in a specific search space may include the controlsignaling, but in some embodiments perhaps not in another search space.

The WTRU may determine the type of the PDCCH (and/or DCI) as a functionof a CRC polynomial. For example, the WTRU may determine that thecontrol signaling is included in the PDCCH as a function of a CRCpolynomial that may be used to determine the format and/or contents ofthe PDCCH.

Techniques used to enable PDSCH and/or PUSCH processing of multiplecarriers/cells/TTIs from a single PDCCH and/or E-PDCCH may comprise oneor more ways in which a WTRU determines the carriers/cells/TTIs to whichthe control signaling discussed herein is applicable. For example, theWTRU may determine that the control signaling is applicable to one cellor to a plurality of cells applicable using methods similar as for thereception of the control information described herein. The plurality ofcells may correspond to a group of cells.

For example, the WTRU may determine the applicable cell(s) as a functionof one or more of: an identity of the cell(s) inside the DCI, across-carrier scheduling association with the cell on which the PDCCH isreceived, the RNTI used to decode the PDCCH of the DCI, the location ofthe PDCCH of the DCI, the search space associated with the received DCI,and/or a CRC polynomial used to decode the PDCCH of the DCI, and/orusing an indication (e.g. a bitmap) inside the received PDCCH.

Grouping of serving cells or TTIs may reduce overhead. PDCCH/E-PDCCH orMAC signaling may incur overhead. A WTRU may use a concept of a group ofserving cells and interpret the values of certain fields based on thegroup of serving cells or TTIs that is related to the PDCCH/E-PDCCH orMAC signaling. (e.g., as a function of the group of serving cells orTTIs) The group of serving cells or TTIs may include a set of servingcells or TTIs configured explicitly or implicitly by higher layers. Thegroup may be a pre-defined or configured number of serving cells pergroup. The order of groups may be implicitly defined from the order ofthe configuration of serving cells or TTIs. For example, if the numberof serving cells per group is defined to be 8, a first group may includethe first 8 configured serving cells, and a second group may include the8 following configured serving cells, and so on. For example, theconfiguration related to a serving cell or TTI may include a fieldindicating a group identity. The group identity may be one or more of aconfigured number of serving cells ordered implicitly, an identifiednumber of serving cells for which a WTRU reports aperiodic CSI in agiven value of the aperiodic CSI field, a given value of a carrierindication field, a certain bit position within anActivation/Deactivation MAC control element, and/or the like

The group identity may be associated with aperiodic CSI triggering. Theset of serving cells for which the WTRU may report aperiodic CSI inPUSCH for a given value of the aperiodic CSI field may be determinedfrom a combination of higher layer signaling and/or one or more of thefollowing. The set of serving cells may be determined from a combinationof higher layer signaling and/or the serving cell from which thePDCCH/E-PDCCH containing the UL grant may be received, or the group ofserving cells to which it belongs. The set of serving cells may bedetermined from a combination of higher layer signaling and/or the groupof serving cells to which the serving cell from which the PDCCH/E-PDCCHcontaining the UL grant belongs. The set of serving cells may bedetermined from a combination of higher layer signaling and/or theserving cell of the PUSCH transmission containing the aperiodic CSIreport. The set of serving cells may be determined from a combination ofhigher layer signaling and/or the group of serving cells to which theserving cell of the PUSCH transmission containing the aperiodic CSIreport belongs.

For example, the WTRU may report CSI for a first set of serving cellsconfigured by higher layers when the value of the aperiodic CSI field isset to “11” and/or the PUSCH is for a serving cell that is part of afirst group of serving cells. The WTRU may report CSI for a second setof serving cells configured by higher layers when the value of theaperiodic CSI field is set to “11” and/or the PUSCH is for a servingcell that is part of a second group of serving cells. In this example,the WTRU may be allowed to transmit CSI over more than one PUSCH.

In another example, the WTRU may report CSI for a first set of servingcells configured by higher layers when the value of the aperiodic CSTfield is set to “11” and/or the PDCCH/E-PDCCH may be received from aserving cell that is part of a first group of serving cells. The WTRUmay report CSI for a second set of serving cells configured by higherlayers when the value of the aperiodic CSI field is set to “11” and/orthe PDCCH/E-PDCCH may be received from a serving cell that is part of asecond group of serving cells.

In some example, the WTRU may implement such techniques without beingconfigured with multiple serving cells in the uplink.

The group identity may be defined such that the carrier indicator field(CIF) interpretation may be dependent on a serving cell over which thePDCCH/E-PDCCH was received. For example, the WTRU may receive a DCI viaa first “scheduling cell” (e.g., scheduling cell may refer to the cellover which the PDCCH/E-PDCCH/DCI was received). The DCI may include acarrier indicator field that indicates an index value. For example, theCIF may be three bits, meaning that it could distinctly refer to up toeight different “scheduled cells” (e.g., the scheduled cell may refer tothe cell over which the PDSCH/PUSCH transmission is to be performed). Bybasing the interpretation of the CIF on the identity of the schedulingcell over which the DCI was received, more than eight cells can bereferred to using the same 3-bit indication/CIF in the DCI. For example,if the WTRU monitors two scheduling cells that are each associated withdifferent interpretations of the CIF, the scheduled cell could be one of16 different serving cells. Thus, by associating the interpretation ofthe value of the CIF with the identity of the scheduling cell the DCIwas received from, larger number of serving cells may be scheduled whilemaintaining one or more legacy DCI formats.

The association of the CIF interpretation with the scheduling servingcell (e.g., a dependency of the CIF interpretation on the schedulingserving cell) may be realized, for example, based on defining servingcell groups. For example, the if the scheduling serving cell is a memberof the first group, then the CIF may be interpreted to be referring toone or more of the scheduled cells of the first group. If the schedulingserving cell is a member of a second group, then the CIF may beinterpreted to be referring to one or more scheduled cells of the secondgroup.

The association of the CIF interpretation with the scheduling servingcell (e.g., a dependency of the CIF interpretation on the schedulingserving cell) may be realized, for example, by configuring for eachscheduled serving cell a value of the CIF used to refer to the scheduledserving cell and/or by configuring the scheduling cell(s) from which thescheduled serving cell will be scheduled from. For example, whenconfiguring a scheduled serving cell (e.g., the cell over which theshared channel transmission is performed) for carrier aggregation (e.g.,via higher layer RRC signaling), the configuration may indicate whichscheduling cell will be used for provide the DCI applicable to thescheduled cell as well as the value of the CIF that will be used in DCIreceived via the scheduling cell in order to refer to the scheduledcell. In this manner, a given value of the CIF may be assigned tomultiple scheduled serving cells by scheduling the scheduled cells usingdifferent scheduling serving cells.

Thus, when a DCI is received from the scheduling serving cell, the CIFcan be interpreted based on the identity of the scheduling serving cell.In this manner, the carrier indicator field may be interpreteddifferently depending on the scheduling cell over which the DCI isreceived. A given value of the carrier indicator field may refer to acertain serving cell for receipt of the PDSCH/PUSCH transmission whenreceived first a first serving cell, but the given value of the carrierindicator field may refer to a different scheduled serving cell forreceipt of the PDSCH/PUSCH transmission when received via a secondscheduling serving cell. The serving cell to which the given value ofthe carrier indicator field may refer may be determined based on theserving cell of the PDCCH/E-PDCCH. Further, the value of the CIF may beused to indicate where in the PDCCH/E-PDCCH and/or the search space ofthe PDCCH/E-PDCCH the WTRU should attempt to decode the DCI.

The scheduled serving cell to which the given value of the carrierindicator field refers may be determined from a configuration of ascheduling serving cell. Higher layers may provide the configuration ofthe scheduling serving cell. For example, a CIF value of “2” in aPDCCH/E-PDCCH received from a first scheduling serving cell may refer toa first scheduled serving cell. The CIF value of “2” in a PDCCH/E-PDCCHreceived from a second scheduling serving cell may refer to a secondscheduled serving cell, if higher layers configure the two differentscheduled serving cell to which the same CIF value of “2” refersaccording to different scheduling serving cells.

The scheduled serving cell to which the given value of the carrierindicator field refers may be determined from a group of serving cellsto which the scheduling serving cell of the PDCCH/E-PDCCH containing theDCI belongs. For example, a CIF value of “3” in a PDCCH/E-PDCCH receivedfrom a scheduling serving cell belonging to a first group of servingcells may refer to the third scheduled serving cell configured withinthe first group of serving cells. A CIF value of “3” in a PDCCH/E-PDCCHreceived from a scheduling serving cell belonging to a second group ofserving cells may refer to the third scheduled serving cell configuredwithin the second group of serving cells.

The group identity may be associated with MAC activation/de-activation.The serving cell corresponding to a certain bit position or field withinan Activation/Deactivation MAC control element may be dependent on theserving cell from which the MAC control element is received. The servingcell corresponding to a certain bit position or field within anActivation/Deactivation MAC control element may be dependent on thegroup of serving cells to which the serving cell from which the MACcontrol element is received may belong. For instance, the serving cellcorresponding to the field “C2” may be serving cell #9 if the MACcontrol element was received in serving cell #8 where serving cells #8and #9 are part of the same group of serving cells. For example, theserving cell corresponding to the field “C2” may be serving cell #17 ifthe MAC control element was received in serving cell #18 where servingcells #17 and #18 are part of the same group of serving cells.

In another example, a certain bit position or field within anActivation/Deactivation MAC control element may indicate a group ofserving cells instead of a single serving cell. For instance, the field“C3” may indicate activation or deactivation of group #3 of servingcells.

Falsely detecting payload data and misinterpreting them may reducenetwork performance for blind decoding. Distinguishing a correctlydetected DCI and a presumably correct but falsely detected DCI (e.g.,where the WTRU processing indicates that the DCI has been successfullydecoded due to a decoding/processing mistake, but in fact the DCI wasnot meant for the WTRU) may avoid falsely detecting payload data andmisinterpreting them. The WTRU may determine whether decoded informationfrom PDCCH and/or E-PDCCH may correspond to valid DCI for the WTRU. Oneor more techniques may be used to determine the validity of downlinkcontrol information (DCI). For example, a WTRU may determine thevalidity of DCI by verifying the value of a cyclic redundancy check(CRC) that may be masked with a specific RNTI or one of a set ofpossible RNTIs. A WTRU may verify whether one or more fields of the DCIhave valid values. For example, one or more determinations may includeverifying whether all fields of the DCI have valid values. A WTRU maydetermine the validity of DCI based on properties of the set of DCI thatis decoded in the same carriers/cells/TTTs as the carriers/cells/TTIsfor the PDSCH scheduled by the DCI. A WTRU may determine the validity ofDCI based on properties of the set of DCI that is decoded in thedifferent carriers/cells/TTIs from the carriers/cells/TTIs for the PDSCHscheduled by the DCI. The WTRU may determine the validity of DCI basedon verifying the value of a CRC of a determined length. The one or moretechniques used to determine the validity of downlink controlinformation (DCI) may apply to DCI of specific format(s). For example,formats that may correspond to downlink assignments (1a, 2, 2a, 2b, 2c,2d, etc.) and/or any DCI format.

For example, validating that a DCI has been correctly decoded and itintended for the WTRU may be based on the WTRU successfully decodingmultiple DCIs in a given subframe, across multiple/a set of subframes,in a given cell, and/or across multiple cells/a set of cells. Forexample, the WTRU may validate that a DCI was correctly received and wasintended for the WTRU based on receiving multiple DCIs where each wassuccessfully decoded using a WTRU RNTI. If multiple DCIs are not decodedcorrectly (e.g., a single DCI is decoded), the WTRU may determine thatthe DCI is in fact not for the WTRU due to a configuration indicatingthat multiple DCIs should be received. For example, for certain cells,DCI types, and/or TTIs, the WTRU may determine that multiple DCIs are tobe decoded correctly in order to validate the concerned DCI for thecell/DCI type/TTI. For example, if a DCI is decoded for a future TTI,the validation of the DCI may include successfully decoding a DCI forthe present TTI.

The one or more techniques used to determine the validity of downlinkcontrol information (DCI) may include evaluating one or more propertiesof the set of DCI's decoded in the same subframe as the subframecontaining the PDSCH scheduled by the DCI. Determining the validity ofDCI may include evaluating one or more properties of the set of DCI'sdecoded in the same cell as the cell through which the PDSCH scheduledby the DCI is transmitted. Determining the validity of DCI may includeevaluating one or more properties of the set of DCI's decoded in othercells than the cell through which the PDSCH scheduled by the DCI istransmitted.

The properties of the DCIs that may be evaluated in order to determinewhether the DCI(s) are valid may include one or more of the following:the number of DCIs of a given format and/or of any format, the number ofDCIs of any format, the cell(s) in which the DCI's were decoded, and/orgroup thereof, the group of cell(s) in which the DCI's were decoded, thecell corresponding to the PDSCH and/or PUSCH transmission indicated bythe DCI, if applicable, the group of cells corresponding to the PDSCHand/or PUSCH transmission indicated by the DCI, if applicable, whetherthe PDSCH transmission indicated by the DCI may be successfully decodedor not, the content of the DCI, the format of the DCI, the content ofanother DCI, and the format of another DCI.

The one or more techniques used to determine the validity of downlinkcontrol information (DCI) may include determining the validity of a DCIbased on the number of configured cells. The WTRU may determine thevalidity of a DCI based on the number of activated cells. Validitydeterminations may include one or more criteria to be met. Validitydeterminations may include one or more sets of rules to be met. Thecriteria may include verifying the CRC parity bits of the DCI. Thecriteria may include verifying the CRC parity bits of the DCI afterscrambling with the appropriate RNTI. The criteria may include verifyingthat one or more field of the payload is set to a valid possible value.For example, the criteria may include verifying that every field of thepayload is set to a valid possible value.

The WTRU may perform one or more actions as a result of detecting a DCIconsidered valid according to at least a first set of criteria. The WTRUmay perform one or more actions as a result of detecting a DCIconsidered valid according to at least a first set of rules. The rulesand/or criteria may be as described herein. If, for example, the WTRUmay determine DCI validity based on a first set of criteria and/or afirst set of rules, the WTRU may attempt decoding the correspondingPDSCH. For example, if the WTRU may determine DCI validity based on afirst set of criteria and/or a first rules, the WTRU may attemptdecoding the corresponding PDSCH in case of a DCI indicating a PDSCHtransmission. If, for example, the WTRU may determine DCI validity basedon at least a second criteria and/or a second rules, the WTRU mayattempt decoding the corresponding PDSCH and/or may generate HARQ A/Nfor the corresponding PDSCH. For example, if the WTRU may determine DCIvalidity based on at least a second criteria and/or a second rules inaddition to the first criteria and/or the first rules, the WTRU mayattempt decoding the corresponding PDSCH and/or may generate HARQ A/Nfor the corresponding PDSCH. For example, if the WTRU may determine DCIvalidity based on at least a second criteria and/or a second rulesexclusive of the first criteria and/or the first rules, the WTRU mayattempt decoding the corresponding PDSCH and/or may generate HARQ A/Nfor the corresponding PDSCH. If, for example, the WTRU may determine DCIvalidity based on a second set of criteria and/or a second set of rulesas described herein, the WTRU may attempt decoding the correspondingPDSCH and/or may generate HARQ A/N for the corresponding PDSCH. Forexample, if the WTRU may determine DCI validity based on a second set ofcriteria and/or a second set of rules as described herein in addition tothe first criteria and/or the first rules, the WTRU may attempt decodingthe corresponding PDSCH and/or may generate HARQ A/N for thecorresponding PDSCH. For example, if the WTRU may determine DCI validitybased on a second set of criteria and/or a second set of rules asdescribed herein exclusive of the first criteria and/or the first rules,the WTRU may attempt decoding the corresponding PDSCH and/or maygenerate HARQ A/N for the corresponding PDSCH. If, for example, the WTRUmay detect DCI validity based on the first (set of) criteria and/or thefirst (set of) rules, but the WTRU may not determine DCI validity basedon the second (set of) criteria and/or the second (set of) rules, theWTRU may attempt decoding the corresponding PDSCH. For example, if theWTRU may detect DCI validity based on the first (set of) criteria and/orthe first (set of) rules, but the WTRU may not determine DCI validitybased on the second (set of) criteria and/or the second (set of) rules,the WTRU may attempt decoding the corresponding PDSCH.

The one or more techniques used to determine the validity of downlinkcontrol information (DCI) may include evaluating certain conditions. TheWTRU may determine that a DCI may be valid if one or more of thefollowing conditions is satisfied. The conditions may include that theDCI is for a PDSCH or PUSCH in a cell belonging to a first group ofcells. The conditions may include that the DCI is for a PDSCH or PUSCHin a cell belonging to a second group of cells, and/or that at least oneDCI was received for a PDSCH and/or PUSCH in a cell belonging to a firstgroup of cells. The conditions may include that the DCI is for a PDSCHor PUSCH in a cell belonging to a second group of cells, and/or that atleast N DCI's were received for PDSCH and/or PUSCH in cell(s) belongingto the second group of cells. The conditions may include that a field ofthe DCI is set to a specific value, and/or a combination of fields ofthe DCI are set to specific values. For example, the WTRU may determinethat a DCI may be valid at least when the value of a downlink assignmentindex (DAI) field is set to a specific value such as “000”, for example.In another example, the WTRU may determine that a DCI may be valid atleast when the value of a “last downlink assignment indicator” field isset to 1 and/or the value of a DAI field is set to “000”, for example.The field(s) may be part of the “payload” of the DCI, and/or may be usedto mask some bits of the CRC. The conditions may include that thecontents of a second DCI indicates that the DCI may be received. Thesecond DCI may be decoded over PDCCH, E-PDCCH and/or PDSCH). The DCI maybe a downlink assignment for a given cell. The second DCI may indicatethat a downlink assignment may be received for this cell. The conditionsmay include that the contents of a second DCI (decoded over PDCCH,E-PDCCH and/or PDSCH) indicates that a resource is available for thetransmission of HARQ A/N, in case the DCI contains a downlinkassignment. The second DCI may be decoded over PDCCH, E-PDCCH and/orPDSCH. The second DCI may for example include a grant for PUSCH and/orcontain an indication of a resource for PUCCH. The conditions mayinclude that the PDSCH transmission indicated by the DCI (in case of adownlink assignment) may be successfully decoded. For example, theconditions may include that the PDSCH transmission indicated by the DCI,in case of a downlink assignment, may be successfully decoded. Theconditions may include that the number of configured cells (or ofactivated cells) is less than a number M. The number of activated cellsmay be less than a number M. For example, M may be set to 5.

The first and/or second groups of carriers/cells/TTIs may be configuredby higher layers. For example, the first and/or second groups of cellsor TTIs may be configured explicitly by higher layers. A group may bedefined in terms of one or more of the following: carriers of a givenband, carrier(s) corresponding to the Pcell, carrier(s) corresponding tothe Scell, and carrier(s) corresponding to the Scell with PUCCH. Forexample, a group may be defined based on whether the carriers belong toa licensed band or an unlicensed band, for example in case oflicense-assisted access (LAA) operation. For example, a group may bedefined based on whether the carriers belong to a licensed band or anunlicensed band in case of license-assisted access (LAA) operation.

The definition of a first and/or second group as referred to herein maydepend on the cell on which a DCI was decoded. Validity is to bedetermined for the DCI. The definition of a first and/or second group asreferred to herein may depend on the cell corresponding to the PDSCHand/or PUSCH transmission indicated by the DCI.

The one or more techniques used to determine the validity of downlinkcontrol information (DCI) may comprise possible rules for determiningpossible invalid DCI, based on the criteria referred to herein. Thepossible rules may be that the WTRU receives (e.g., at most) X DCI(s)(e.g. X=1) when up to Y serving cells configured with PDCCH areactivated (e.g. Y=all). The possible rules may be that the WTRU receives(e.g., at most) X DCI(s) (e.g. X=1) but none is received on resources ofone (or more) specific cell(s) configured with PDCCH (e.g. at least onePDCCH may be received for a specific group of cells). The possible rulesmay be that the WTRU receives DCI(s) (e.g., only) on resourcesassociated to cells in the unlicensed band (LAA). The possible rules maybe that the WTRU receives DCI(s)/PDCCH transmission(s) on resourcesassociated with cells in the unlicensed band (LAA), but does not haveany scheduling information for uplink transmission on other cells(either for at least one PUSCH transmission, for a PUCCH based on rulesapplicable to cells in the licensed domain, and/or due to the absence ofa DCI(UCI) with dynamic scheduling for UCI transmission).

One or more rules described herein may allow a reduction of occurrencesof falsely determining a valid DCI. The reduction may be significant.The probability of falsely detecting more than one DCI in a subframe maybe low. The probability may be very low. The network may schedule anamount of data using a single DCI. The amount may be small. Thecorresponding PDSCH and/or PUSCH may be in a cell of a given group.

The one or more techniques used to determine the validity of downlinkcontrol information (DCI) may include the use of CRC of one or more(e.g. different) lengths. For example, the WTRU may determine thevalidity of a DCI based on verifying the value of a CRC of a determinedlength. The WTRU may determine the length of the CRC based on one ormore of the following: a search space, a DCI format, the cell (and/orgroup thereof) in which the PDCCH/E-PDCCH is decoded, and/or the cellwhere the indicated PDSCH and/or PUSCH (and/or group thereof) istransmitted. The WTRU may determine the length of the CRC based on asearch space. For example, the WTRU may determine that the CRC length isa first value, e.g. 16, if PDCCH is decoded on the common search space;and a second value, e.g. 24, if PDCCH and/or E-PDCCH is decoded on aWTRU-specific search space. The WTRU may determine the length of the CRCbased on a DCI format. For example, the WTRU may determine that the CRClength is a first value, e.g. 16, if the DCI format is format 0, 1a, 1c,or 4; and a second value, e.g. 24, if the DCI format is format 2a, 2b,2c or 2d;

The one or more techniques used to determine the validity of downlinkcontrol information (DCI) may include the use of CRC scrambling. CRCparity bits may be scrambled (and/or masked) with bits derived from atleast one field. The at least one field may include, for example, one ormore of the following: a radio network temporary identifier (RNTI), aWTRU transmit antenna selection field, a field that may be used todetermine a codebook for HARQ A/N reporting, such as a downlinkassignment index (DAI), an indicator of whether HARQ A/N is to bereported for the PDSCH transmission(s), and/or a codebook indicator, anA/N resource indicator (ARI), and/or any other DCI field.

The scrambling may be performed over a subset and/or the totality of CRCparity bits. For example, scrambling over a subset of CRC parity bitsmay be substantially similar to scrambling the totality of CRC paritybits using a sequence including “0” for the bit positions where noscrambling is taking place.

For example, scrambling may be performed using one or more sequences.The one or more sequences may be added to the CRC parity bits. The oneor more sequences may be added to the CRC parity bits, perhaps forexample before modulo 2 operation. For example, if scrambling isperformed using sequences S1 and S2 corresponding to two differentfields, the output Y of the scrambling operation may be expressed asY=(C+S1+S2) mod 2 where C is the sequence of CRC parity bits.

A scrambling sequence may be determined from the value of a field or acombination of fields. A scrambling sequence may be determined from thevalue of a field or a combination of fields, perhaps for example basedon a pre-determined mapping and/or table. For example, the scramblingsequence may be identical to the binary representation of a field (e.g.for RNTI). The scrambling sequence may be identical to the binaryrepresentation of a field (e.g. for RNTI) perhaps for example, if thebinary representation has the same length as the sequence, among otherscenarios. For example, the scrambling sequence may be a truncatedversion of the binary representation of the field. The scramblingsequence may be a truncated version of the binary representation of thefield, perhaps for example if it is shorter than this binaryrepresentation, among other scenarios. For example, when the scramblingsequence is larger than the binary representation of the field (e.g.,the CRC length or scrambling sequence may be 24 bits, and a RNTI fieldmay be 16 bits), the scrambling sequence may be obtained by one or moreof the following: cyclically extending the binary representation of thefield, appending a fixed sequence of bits to the binary representationof the field (e.g., one or more, or all, “0”, one or more, or all, “1”,and so on), and/or the like.

A scrambling sequence may be generated from the combination of two ormore fields by cyclically shifting the scrambling sequence determinedfrom a first field by a number of positions determined from the value ofa second field. For example, a first field may include a 16 bit RNTI. Asecond field may include a downlink antenna index (DAI), which forexample may take 8 possible values (e.g., 0 to 7). A scrambling sequenceof 24 bits may be generated by cyclically shifting the binaryrepresentation of the RNTI by a number of positions corresponding to 3times the value of the DAI. For example, cyclically shifting the binaryrepresentation of the RNTI may include extending as per one or more ofthe techniques described herein by a number of positions correspondingto 3 times the value of the DAI.

The WTRU may use the value of the scrambled (and/or masked) CRC sequenceto determine whether the DCI may be valid. The WTRU may use the value ofthe scrambled (and/or masked) CRC sequence to determine whether the DCImay be valid, perhaps for example when receiving DCI from PDCCH and/orE-PDCCH. The WTRU may use the value of the scrambled (and/or masked) CRCsequence to determine the value of at least one field used to scramblethe DCI. The WTRU may use the value of the scrambled (and/or masked) CRCsequence to determine the value of at least one field used to scramblethe DCI, perhaps for example when receiving DCI from PDCCH and/orE-PDCCH. The WTRU may, for example, perform one or more of thefollowing. The WTRU may determine the sequence of CRC parity bits C′based on the received payload bits. The WTRU may descramble the receivedsequence Y of scrambled CRC parity bits using a sequence S=(S1+S2+S3+ .. . ) mod 2 corresponding to a valid possible combination of values ofthe corresponding fields. The WTRU may determine whether the descrambledsequence (Y+S1+S2+S3+ . . . ) mod 2 matches the sequence C′. If thedescrambled sequence (Y+S1+S2+S3+ . . . ) mod 2 matches the sequence C′,the DCI may be considered valid. The DCI may be considered valid,possibly subject to other conditions as techniques described herein. Ifthe descrambled sequence (Y+S1+S2+S3+) mod 2 matches the sequence C′,the values of one or more field may be determined to be the ones usedfor determining the sequence S. For example, if the descrambled sequence(Y+S1+S2+S3+) mod 2 matches the sequence C′, the values of each fieldmay be determined to be the ones used for determining the sequence S. Ifthe descrambled sequence (Y+S1+S2+S3+ . . . ) mod 2 does not match thesequence C′, the WTRU may descramble the sequence Y using another validpossible combination of values of the fields. The WTRU may determinethat the DCI is not valid if the descrambled sequence does not match thesequence C′ for any valid possible combination of values of the fields

The following examples may illustrate how the WTRU may use thetechniques above to determine whether the DCI may be valid. In theexamples, the sequence of CRC parity bits includes 24 bits. In theexamples, one or more of the following fields may be used forscrambling: RNTI, Downlink antenna indicator (DAI), and/or the like.

In an example, the scrambling sequence S1 corresponding to RNTI fieldmay include the 16 bits of the binary representation of the RNTIfollowed by 8 zeros. The scrambling sequence S2 corresponding to DAI mayinclude 16 zeros that may be followed by the binary representation ofthe DAI which may be 8 bits in this example (perhaps for example if DAIhas values ranging from 0 to 255). The WTRU may determine validity ofthe DCI by descrambling the sequence Y using S1 and/or determiningwhether the 16 first bits of the resulting sequence Z match the 16 firstbits of the sequence of CRC parity bits C′, perhaps for example based onthe payload. If the 16 first bits match, the WTRU may consider that theDCI may be valid. The WTRU may determine the value of the DAI field byidentifying the sequence S2 for which (Y+S1+S2) mod 2 corresponds to C′for the 8 last bits. The value of S2 may be determined as (Y+C′) mod 2,perhaps for example since S1 may be 0 for the last 8 bits, among otherscenarios. If there is not a match for the 16 first bits, the WTRU mayconsiders that the DCI may not be valid.

In an example, the scrambling sequence S1 corresponding to RNTI fieldmay include the 16 bits of the binary representation of the RNTI thatmay be followed by the 8 first bits of the same representation. Thescrambling sequence S2 corresponding to DAI (which may be 6 bits forexample) may include the binary representation of the DAI repeated 4times. The WTRU may determine validity of the DCI by verifying if thesequence (Y+S1+S2) mod 2 corresponds to C′ for at least one of the 64possible S2 sequences. If there is a match for at least one of thesequences, the WTRU may consider that the DCI may be valid. The DAIvalue may be identified as at least one that may correspond to thematching sequence. If there is no match for any one of the sequences,the WTRU may consider that the DCI may not be valid.

Although features and elements are described above in particularcombinations, one of ordinary skill in the art will appreciate that eachfeature or element can be used alone or in any combination with theother features and elements. In addition, the methods described hereinmay be implemented in a computer program, software, or firmwareincorporated in a computer-readable medium for execution by a computeror processor. Examples of computer-readable media include electronicsignals (transmitted over wired or wireless connections) andcomputer-readable storage media. Examples of computer-readable storagemedia include, but are not limited to, a read only memory (ROM), arandom access memory (RAM), a register, cache memory, semiconductormemory devices, magnetic media such as internal hard disks and removabledisks, magneto-optical media, and optical media such as CD-ROM disks,and digital versatile disks (DVDs). A processor in association withsoftware may be used to implement a radio frequency transceiver for usein a WTRU, WTRU, terminal, base station, RNC, or any host computer.

1-60. (canceled)
 61. A wireless transmit/receive unit (WTRU) comprising:a processor configured to: receive a radio resource control (RRC)configuration message, wherein the RRC configuration message indicatesthat a third serving cell is scheduled when a carrier indicator field(CIF) value is received via a first serving cell and that a fourthserving cell is scheduled when the CIF value is received via a secondserving cell; receive a first downlink control information (DCI) via afirst downlink control channel of the first serving cell, wherein thefirst DCI comprises the CIF value; determine that the first DCIcomprises scheduling information for the third serving cell based on thefirst DCI comprising the CIF value and the RRC configuration message;perform a first wireless communication based on the determination thatthe first DCI comprises the scheduling information for the third servingcell; receive a second downlink control information (DCI) via a seconddownlink control channel of the second serving cell, wherein the secondDCI comprises the CIF value; determine that the second DCI comprisesscheduling information for the fourth serving cell based the second DCIcomprising the CIF value and the RRC configuration message; and performa second wireless communication based on the determination that thesecond DCI comprises the scheduling information for the fourth servingcell.
 62. The WTRU of claim 61, wherein the scheduling information forthe third serving cell comprises an uplink grant.
 63. The WTRU of claim62, wherein, to perform the first wireless communication, the processoris configured to send a physical uplink shared channel transmissionusing the uplink grant.
 64. The WTRU of claim 61, wherein the schedulinginformation for the third serving cell comprises a downlink allocation.65. The WTRU of claim 64, wherein, to perform the first wirelesscommunication, the processor is configured to receive a physicaldownlink shared channel transmission using the downlink allocation. 66.The WTRU of claim 61, wherein the processor is configured to interpretthe CIF value in the first DCI based on an identity of the first servingcell over which the first DCI has been received.
 67. A method performedby a wireless transmit/receive unit (WTRU), comprising: receiving aradio resource control (RRC) configuration message, wherein the RRCconfiguration message indicates that a third serving cell is scheduledwhen a carrier indicator field (CIF) value is received via a firstserving cell and that a fourth serving cell is scheduled when the CIFvalue is received via a second serving cell; receiving a first downlinkcontrol information (DCI) via a first downlink control channel of thefirst serving cell, wherein the first DCI comprises the CIF value;determining that the first DCI comprises scheduling information for thethird serving cell based on the first DCI comprising the CIF value andthe RRC configuration message; performing a first wireless communicationbased on the determination that the first DCI comprises the schedulinginformation for the third serving cell; receiving a second downlinkcontrol information (DCI) via a second downlink control channel of thesecond serving cell, wherein the second DCI comprises the CIF value;determining that the second DCI comprises scheduling information for thefourth serving cell based the second DCI comprising the CIF value andthe RRC configuration message; and performing a second wirelesscommunication based on the determination that the second DCI comprisesthe scheduling information for the fourth serving cell.
 68. The methodof claim 67, wherein the scheduling information for the third servingcell comprises an uplink grant, and wherein performing the firstwireless communication comprises sending a physical uplink sharedchannel transmission using the uplink grant.
 69. The method of claim 67,wherein the scheduling information for the third serving cell comprisesa downlink allocation, and wherein performing the first wirelesscommunication comprises receiving a physical downlink shared channeltransmission using the downlink allocation.
 70. The method of claim 67,further comprising interpreting the CIF value in the first DCI based onan identity of the first serving cell over which the first DCI has beenreceived.
 71. A wireless transmit/receive unit (WTRU) comprising: aprocessor configured to: receive a radio resource control (RRC)configuration message, wherein the RRC configuration message associatesa scheduling serving cell, a carrier indicator field (CIF) value, and ascheduled serving cell that differs from the scheduling serving cell;receive the CIF value and scheduling information in a downlink controlinformation (DCI) via the scheduling serving cell; and perform awireless communication on the scheduled serving cell according to thereceived CIF value, the scheduling serving cell, and the RRCconfiguration message.
 72. The WTRU of claim 71, wherein the RRCconfiguration message associates the scheduling serving cell, the CIFvalue, and the scheduled serving cell that differs from the schedulingserving cell such that the CIF value is used to refer to the scheduledserving cell based on the scheduling serving cell from which the CIF isreceived.
 73. The WTRU of claim 71, wherein the RRC configurationmessage indicates which scheduling serving cell is to be used to providethe DCI applicable to the scheduled serving cell and indicates the CIFvalue that refers to the scheduled serving cell.
 74. The WTRU of claim71, wherein the RRC configuration message associates the schedulingserving cell, the CIF value, and the scheduled serving cell that differsfrom the scheduling serving cell such that the CIF value is assigned toa plurality of scheduled serving cells by scheduling the scheduledserving cells using different scheduling serving cells.
 75. The WTRU ofclaim 71, wherein the CIF value is indicated in a 3-bit carrierindicator field.